Chapter 9. To Boston Via The Road Go I, With An Excursion Into The Land Of Modals

The basic type of Lojban sentence is the bridi: a claim by the speaker that certain objects are related in a certain way. The objects are expressed by Lojban grammatical forms called sumti; the relationship is expressed by the Lojban grammatical form called a selbri.

The sumti are not randomly associated with the selbri, but according to a systematic pattern known as the “place structure” of the selbri. This chapter describes the various ways in which the place structure of Lojban bridi is expressed and by which it can be manipulated. The place structure of a selbri is a sequence of empty slots into which the sumti associated with that selbri are placed. The sumti are said to occupy the places of the selbri.

For our present purposes, every selbri is assumed to have a well-known place structure. If the selbri is a brivla, the place structure can be looked up in a dictionary (or, if the brivla is a lujvo not in any dictionary, inferred from the principles of lujvo construction as explained in Chapter 12); if the selbri is a tanru, the place structure is the same as that of the final component in the tanru.

The stock example of a place structure is that of the gismu klama:

The “x1 ... x5” indicates that klama is a five-place predicate, and show the natural order (as assigned by the language engineers) of those places: agent, destination, origin, route, means.

The place structures of brivla are not absolutely stable aspects of the language. The work done so far has attempted to establish a basic place structure on which all users can, at first, agree. In the light of actual experience with the individual selbri of the language, there will inevitably be some degree of change to the brivla place structures.

The following cmavo is discussed in this section:

The most usual way of constructing a bridi from a selbri such as klama and an appropriate number of sumti is to place the sumti intended for the x1 place before the selbri, and all the other sumti in order after the selbri, thus:

Here the sumti are assigned to the places as follows:

(Note: Many of the examples in the rest of this chapter will turn out to have the same meaning as Example 9.1; this fact will not be reiterated.)

This ordering, with the x1 place before the selbri and all other places in natural order after the selbri, is called “standard bridi form”, and is found in the bulk of Lojban bridi, whether used in main sentences or in subordinate clauses. However, many other forms are possible, such as:

Here the selbri is at the end; all the sumti are placed before it. However, the same order is maintained.

Similarly, we may split up the sumti, putting some before the selbri and others after it:

All of the variant forms in this section and following sections can be used to place emphasis on the part or parts which have been moved out of their standard places. Thus, Example 9.2 places emphasis on the selbri (because it is at the end); Example 9.3 emphasizes la bastn., because it has been moved before the selbri. Moving more than one component may dilute this emphasis. It is permitted, but no stylistic significance has yet been established for drastic reordering.

In all these examples, the cmavo cu (belonging to selma'o CU) is used to separate the selbri from any preceding sumti. It is never absolutely necessary to use cu. However, providing it helps the reader or listener to locate the selbri quickly, and may make it possible to place a complex sumti just before the selbri, allowing the speaker to omit elidable terminators, possibly a whole stream of them, that would otherwise be necessary.

The general rule, then, is that the selbri may occur anywhere in the bridi as long as the sumti maintain their order. The only exception (and it is an important one) is that if the selbri appears first, the x1 sumti is taken to have been omitted:

Here the x1 place is empty: the listener must guess from context who is going to Boston. In Example 9.4, klama is glossed “a goer” rather than “go” because “Go” at the beginning of an English sentence would suggest a command: “Go to Boston!”. Example 9.4 is not a command, simply a normal statement with the x1 place unspecified, causing the emphasis to fall on the selbri klama. Such a bridi, with empty x1, is called an “observative”, because it usually calls on the listener to observe something in the environment which would belong in the x1 place. The third translation above shows this observative nature. Sometimes it is the relationship itself which the listener is asked to observe.

(There is a way to both provide a sumti for the x1 place and put the selbri first in the bridi: see Example 9.14.)

Suppose the speaker desires to omit a place other than the x1 place? (Presumably it is obvious or, for one reason or another, not worth saying.) Places at the end may simply be dropped:

Example 9.5 has empty x4 and x5 places: the speaker does not specify the route or the means of transport. However, simple omission will not work for a place when the places around it are to be specified: in

le karce occupies the x4 place, and therefore Example 9.6 means:

This is nonsense, since a car cannot be a route. What the speaker presumably meant is expressed by:

Here the sumti cmavo zo'e is used to explicitly fill the x4 place; zo'e means “the unspecified thing” and has the same meaning as leaving the place empty: the listener must infer the correct meaning from context.

The following cmavo are discussed in this section:

In sentences like Example 9.1, it is easy to get lost and forget which sumti falls in which place, especially if the sumti are more complicated than simple names or descriptions. The place structure tags of selma'o FA may be used to help clarify place structures. The five cmavo fa, fe, fi, fo, and fu may be inserted just before the sumti in the x1 to x5 places respectively:

In Example 9.8, the tag fu before le karce clarifies that le karce occupies the x5 place of klama. The use of fu tells us nothing about the purpose or meaning of the x5 place; it simply says that le karce occupies it.

In Example 9.8, the tags are overkill; they serve only to make Example 9.1 even longer than it is. Here is a better illustration of the use of FA tags for clarification:

In Example 9.9, the place structure of klama is as follows:

The fi tag serves to remind the hearer that what follows is in the x3 place of klama; after listening to the complex sumti occupying the x2 place, it's easy to get lost.

Of course, once the sumti have been tagged, the order in which they are specified no longer carries the burden of distinguishing the places. Therefore, it is perfectly all right to scramble them into any order desired, and to move the selbri to anywhere in the bridi, even the beginning:

Note that no cu is permitted before the selbri in Example 9.10, because cu separates the selbri from any preceding sumti, and Example 9.10 has no such sumti.

Example 9.11 exhibits the reverse of the standard bridi form seen in Example 9.1 and Example 9.8, but still means exactly the same thing. If the FA tags were left out, however, producing:

the meaning would be wholly changed, and in fact nonsensical.

Tagging places with FA cmavo makes it easy not only to reorder the places but also to omit undesirable ones, without any need for zo'e or special rules about the x1 place:

Here the x1 and x4 places are empty, and so no sumti are tagged with fa or fo; in addition, the x2 and x3 places appear in reverse order.

What if some sumti have FA tags and others do not? The rule is that after a FA-tagged sumti, any sumti following it occupy the places numerically succeeding it, subject to the proviso that an already-filled place is skipped:

In Example 9.14, the fa causes mi to occupy the x1 place, and then the following untagged sumti occupy in order the x2 through x5 places. This is the mechanism by which Lojban allows placing the selbri first while specifying a sumti for the x1 place.

Here is a more complex (and more confusing) example:

In Example 9.15, mi occupies the x1 place because it is the first sumti in the sentence (and is before the selbri). The second sumti, la .atlantas., occupies the x3 place by virtue of the tag fi, and le dargu occupies the x4 place as a result of following la .atlantas.. Finally, la bastn. occupies the x2 place because of its tag fe, and le karce skips over the already-occupied x3 and x4 places to land in the x5 place.

Such a convoluted use of tags should probably be avoided except when trying for a literal translation of some English (or other natural-language) sentence; the rules stated here are merely given so that some standard interpretation is possible.

It is grammatically permitted to tag more than one sumti with the same FA cmavo. The effect is that of making more than one claim:

may be taken to say that both Rick and Jane go to the movie, the house, and the office, merging six claims into one. More likely, however, it will simply confuse the listener. There are better ways, involving logical connectives (explained in Chapter 14), to say such things in Lojban. In fact, putting more than one sumti into a place is odd enough that it can only be done by explicit FA usage: this is the motivation for the proviso above, that already-occupied places are skipped. In this way, no sumti can be forced into a place already occupied unless it has an explicit FA cmavo tagging it.

The cmavo fi'a also belongs to selma'o FA, and allows Lojban users to ask questions about place structures. A bridi containing fi'a is a question, asking the listener to supply the appropriate other member of FA which will make the bridi a true statement:

In Example 9.17, the speaker uses the selbri dunda, whose place structure is:

The tagged sumti fi'a do indicates that the speaker wishes to know whether the sumti do falls in the x1 or the x3 place (the x2 place is already occupied by le rozgu). The listener can reply with a sentence consisting solely of a FA cmavo: fa if the listener is the giver, fi if he/she is the receiver.

I have inserted the tag fe in brackets into Example 9.17, but it is actually not necessary, because fi'a does not count as a numeric tag; therefore, le vi rozgu would necessarily be in the x2 place even if no tag were present, because it immediately follows the selbri.

There is also another member of FA, namely fai, which is discussed in Section 9.12.

The following cmavo are discussed in this section:

So far we have seen ways to move sumti around within a bridi, but the actual place structure of the selbri has always remained untouched. The conversion cmavo of selma'o SE are incorporated within the selbri itself, and produce a new selbri (called a converted selbri) with a different place structure. In particular, after the application of any SE cmavo, the number and purposes of the places remain the same, but two of them have been exchanged, the x1 place and another. Which place has been exchanged with x1 depends on the cmavo chosen. Thus, for example, when se is used, the x1 place is swapped with the x2 place.

Note that the cmavo of SE begin with consecutive consonants in alphabetical order. There is no “1st place conversion” cmavo, because exchanging the x1 place with itself is a pointless maneuver.

Here are the place structures of se klama:

and te klama:

and ve klama:

and xe klama:

Note that the place structure numbers in each case continue to be listed in the usual order, x1 to x5.

Consider the following pair of examples:

Example 9.18 and Example 9.19 mean the same thing, in the sense that there is a relationship of going with the speaker as the agent and Boston as the destination (and with unspecified origin, route, and means). Structurally, however, they are quite different. Example 9.18 has la bastn. in the x1 place and mi in the x2 place of the selbri se klama, and uses standard bridi order; Example 9.19 has mi in the x1 place and la bastn. in the x2 place of the selbri klama, and uses a non-standard order.

The most important use of conversion is in the construction of descriptions. A description is a sumti which begins with a cmavo of selma'o LA or LE, called the descriptor, and contains (in the simplest case) a selbri. We have already seen the descriptions le dargu and le karce. To this we could add:

In every case, the description is about something which fits into the x1 place of the selbri. In order to get a description of a destination (that is, something fitting the x2 place of klama), we must convert the selbri to se klama, whose x1 place is a destination. The result is

Likewise, we can create three more converted descriptions:

Example 9.23 does not mean “the route” plain and simple: that is le pluta, using a different selbri. It means a route that is used by someone for an act of klama; that is, a journey with origin and destination. A “road” on Mars, on which no one has traveled or is ever likely to, may be called le pluta, but it cannot be le ve klama, since there exists no one for whom it is le ve klama be fo da (the route taken in an actual journey by someone [da]).

When converting selbri that are more complex than a single brivla, it is important to realize that the scope of a SE cmavo is only the following brivla (or equivalent unit). In order to convert an entire tanru, it is necessary to enclose the tanru in ke…ke'e brackets:

The place structure of blanu zdani (blue house) is the same as that of zdani, by the rule given in Section 9.1. The place structure of zdani is:

The place structure of se ke blanu zdani [ke'e] is therefore:

Consequently, Example 9.25 means:

Conversion applied to only part of a tanru has subtler effects which are explained in Section 5.11.

It is grammatical to convert a selbri more than once with SE; later (inner) conversions are applied before earlier (outer) ones. For example, the place structure of se te klama is achieved by exchanging the x1 and x2 place of te klama, producing:

On the other hand, te se klama has a place structure derived from swapping the x1 and x3 places of se klama:

which is quite different. However, multiple conversions like this are never necessary. Arbitrary scrambling of places can be achieved more easily and far more intelligibly with FA tags, and only a single conversion is ever needed in a description.

(Although no one has made any real use of it, it is perhaps worth noting that compound conversions of the form setese, where the first and third cmavo are the same, effectively swap the two given places while leaving the others, including x1, alone: setese (or equivalently tesete) swap the x2 and x3 places, whereas texete (or xetexe) swap the x3 and x5 places.)

The following cmavo are discussed in this section:

Sometimes the place structures engineered into Lojban are inadequate to meet the needs of actual speech. Consider the gismu viska, whose place structure is:

Seeing is a threefold relationship, involving an agent (le viska), an object of sight (le se viska), and an environment that makes seeing possible (le te viska). Seeing is done with one or more eyes, of course; in general, the eyes belong to the entity in the x1 place.

Suppose, however, that you are blind in one eye and are talking to someone who doesn't know that. You might want to say, “I see you with the left eye.” There is no place in the place structure of viska such as “with eye x4” or the like. Lojban allows you to solve the problem by adding a new place, changing the relationship:

The three-place relation viska has now acquired a fourth place specifying the eye used for seeing. The combination of the cmavo fi'o (of selma'o FIhO) followed by a selbri, in this case the gismu kanla, forms a tag which is prefixed to the sumti filling the new place, namely le zunle. The semantics of fi'o kanla le zunle is that le zunle fills the x1 place of kanla, whose place structure is

Thus le zunle is an eye. The x2 place of kanla is unspecified and must be inferred from the context. It is important to remember that even though le zunle is placed following fi'o kanla, semantically it belongs in the x1 place of kanla. The selbri may be terminated with fe'u (of selma'o FEhU), an elidable terminator which is rarely required unless a non-logical connective follows the tag (omitting fe'u in that case would make the connective affect the selbri).

The term for such an added place is a “modal place”, as distinguished from the regular numbered places. (This use of the word “modal” is specific to the Loglan Project, and does not agree with the standard uses in either logic or linguistics, but is now too entrenched to change easily.) The fi'o construction marking a modal place is called a “modal tag”, and the sumti which follows it a “modal sumti”; the purely Lojban terms sumti tcita and seltcita sumti, respectively, are also commonly used. Modal sumti may be placed anywhere within the bridi, in any order; they have no effect whatever on the rules for assigning unmarked bridi to numbered places, and they may not be marked with FA cmavo.

Consider Example 9.26 again. Another way to view the situation is to consider the speaker's left eye as a tool, a tool for seeing. The relevant selbri then becomes pilno, whose place structure is

and we can rewrite Example 9.26 as

Here the selbri belonging to the modal is se pilno. The conversion of pilno is necessary in order to get the “tool” place into x1, since only x1 can be the modal sumti. The “tool user” place is the x2 of se pilno (because it is the x1 of pilno) and remains unspecified. The tag fi'o pilno would mean “with tool user”, leaving the tool unspecified.

There are certain selbri which seem particularly useful in constructing modal tags. In particular, pilno is one of them. The place structure of pilno is:

and almost any selbri which represents an action may need to specify a tool. Having to say fi'o se pilno frequently would make many Lojban sentences unnecessarily verbose and clunky, so an abbreviation is provided in the language design: the compound cmavo sepi'o.

Here se is used before a cmavo, namely pi'o, rather than before a brivla. The meaning of this cmavo, which belongs to selma'o BAI, is exactly the same as that of fi'o pilno fe'u. Since what we want is a tag based on se pilno rather than pilno- the tool, not the tool user – the grammar allows a BAI cmavo to be converted using a SE cmavo. Example 9.27 may therefore be rewritten as:

The compound cmavo sepi'o is much shorter than fi'o se pilno [fe'u] and can be thought of as a single word meaning “with-tool”. The modal tag pi'o, with no se, similarly means “with-tool-user”, probably a less useful concept. Nevertheless, the parallelism with the place structure of pilno makes the additional syllable worthwhile.

Some BAI cmavo make sense with as well as without a SE cmavo; for example, ka'a, the BAI corresponding to the gismu klama, has five usable forms corresponding to the five places of klama respectively:

Any of these tags may be used to provide modal places for bridi, as in the following examples:

(Example 9.29 may seem a bit strained, but it illustrates the way in which an existing selbri, vecnu in this case, may have a place added to it which might otherwise seem utterly unrelated.)

There are sixty-odd cmavo of selma'o BAI, based on selected gismu that seemed useful in a variety of settings. The list is somewhat biased toward English, because many of the cmavo were selected on the basis of corresponding English prepositions and preposition compounds such as “with”, “without”, and “by means of”. The BAI cmavo, however, are far more precise than English prepositions, because their meanings are fixed by the place structures of the corresponding gismu.

All BAI cmavo have the form CV'V or CVV. Most of them are CV'V, where the C is the first consonant of the corresponding gismu and the two Vs are the two vowels of the gismu. The table in Section 9.16 shows the exceptions.

There is one additional BAI cmavo that is not derived from a gismu: do'e. This cmavo is used when an extra place is needed, but it seems useful to be vague about the semantic implications of the extra place:

Here le berti is provided as a modal place of the selbri nanmu, but its exact significance is vague, and is paralleled in the colloquial translation by the vague English preposition “of”. Example 9.34 also illustrates a modal place bound into a selbri with be. This construction is useful when the selbri of a description requires a modal place; this and other uses of be are more fully explained in Section 5.7.

The following cmavo are discussed in this section:

This section has two purposes. On the one hand, it explains the grammatical construct called “modal sentence connection”. On the other, it exemplifies some of the more useful BAI cmavo: the causals. (There are other BAI cmavo which have causal implications: ja'e means “with result”, and so seja'e means “with cause of unspecified nature”; likewise, gau means “with agent” and tezu'e means “with purpose”. These other modal cmavo will not be further discussed here, as my purpose is to explain modal sentence connection rather than Lojbanic views of causation.)

There are four causal gismu in Lojban, distinguishing different versions of the relationships lumped in English as “causal”:

Each of these gismu has a related modal: ri'a, ki'u, mu'i, and ni'i respectively. Using these gismu and these modals, we can create various causal sentences with different implications:

In Example 9.35 through Example 9.38, the same English word “because” is used to translate all four modals, but the types of cause being expressed are quite different. Let us now focus on Example 9.35, and explore some variations on it.

As written, Example 9.35 claims that the plant grows, but only refers to the event of watering it in an abstraction bridi (abstractions are explained in Chapter 11) without actually making a claim. If I express Example 9.35, I have said that the plant in fact grows, but I have not said that you actually water it, merely that there is a causal relationship between watering and growing. This is semantically asymmetrical. Suppose I wanted to claim that the plant was being watered, and only mention its growth as ancillary information? Then we could reverse the main bridi and the abstraction bridi, saying:

with the ri'a changed to seri'a. In addition, there are also symmetrical forms:

does not claim either event, but asserts only the causal relationship between them. So in Example 9.40, I am not saying that the plant grows nor that you have in fact watered it. The second colloquial translation shows a form of “if-then” in English quite distinct from the logical connective “if-then” explained in Chapter 14.

Suppose we wish to claim both events as well as their causal relationship? We can use one of two methods:

The compound cmavo .iri'abo and .iseri'abo serve to connect two bridi, as the initial i indicates. The final bo is necessary to prevent the modal from “taking over” the following sumti. If the bo were omitted from Example 9.41 we would have:

Because ri'a do is a modal sumti in Example 9.43, there is no longer an explicit sumti in the x1 place of djacu dunda, and the translation must be changed.

The effect of sentences like Example 9.41 and Example 9.42 is that the modal, ri'a in this example, no longer modifies an explicit sumti. Instead, the sumti is implicit, the event given by a full bridi. Furthermore, there is a second implication: that the first bridi fills the x2 place of the gismu rinka; it specifies an event which is the effect. I am therefore claiming three things: that the plant grows, that you have watered it, and that there is a cause-and-effect relationship between the two.

In principle, any modal tag can appear in a sentence connective of the type exemplified by Example 9.41 and Example 9.42. However, it makes little sense to use any modals which do not expect events or other abstractions to fill the places of the corresponding gismu. The sentence connective .ibaubo is perfectly grammatical, but it is hard to imagine any two sentences which could be connected by an “in-language” modal. This is because a sentence describes an event, and an event can be a cause or an effect, but not a language.

Like many Lojban grammatical constructions, sentence modal connection has both forethought and afterthought forms. (See Chapter 14 for a more detailed discussion of Lojban connectives.) Section 9.7 exemplifies only afterthought modal connection, illustrated here by:

An afterthought connection is one that is signaled only by a cmavo (or a compound cmavo, in this case) between the two constructs being connected. Forethought connection uses a signal both before the first construct and between the two: the use of “both” and “and” in the first half of this sentence represents a forethought connection (though not a modal one).

To make forethought modal sentence connections in Lojban, place the modal plus gi before the first bridi, and gi between the two. No i is used within the construct. The forethought equivalent of Example 9.44 is:

Note that the cause, the x1 of rinka is now placed first. To keep the two bridi in the original order of Example 9.44, we could say:

In English, the sentence “Therefore I grasp the water, I grasp the cup” is ungrammatical, because “therefore” is not grammatically equivalent to “because”. In Lojban, seri'agi can be used just like ri'agi.

When the two bridi joined by a modal connection have one or more elements (selbri or sumti or both) in common, there are various condensed forms that can be used in place of full modal sentence connection with both bridi completely stated.

When the bridi are the same except for a single sumti, as in Examples 8.1 through 8.3, then a sumti modal connection may be employed:

Example 9.47 means exactly the same as Example 9.44 through Example 9.46, but there is no idiomatic English translation that will distinguish it from them.

If the two connected bridi are different in more than one sumti, then a termset may be employed. Termsets are explained more fully in Section 14.11, but are essentially a mechanism for creating connections between multiple sumti simultaneously.

means the same as:

Here there are three sumti in each half of the termset, because the two bridi share only their selbri.

There is no modal connection between selbri as such: bridi which differ only in the selbri can be modally connected using bridi-tail modal connection. The bridi-tail construct is more fully explained in Section 14.9, but essentially it consists of a selbri with optional sumti following it. Example 9.37 is suitable for bridi-tail connection, and could be shortened to:

Again, no straightforward English translation exists. It is even possible to shorten Example 9.50 further to:

where le cukta is set off by the non-elidable vau and is made to belong to both bridi-tails – see Section 14.9 for more explanations.

Since this is a chapter on rearranging sumti, it is worth pointing out that Example 9.51 can be further rearranged to:

which doesn't require the extra vau; all sumti before a conjunction of bridi-tails are shared.

Finally, mathematical operands can be modally connected.

can be reduced to:

The cmavo vei and ve'o represent mathematical parentheses, and are required so that ni'igi affects more than just the immediately following operand, namely the first re. (The right parenthesis, ve'o, is an elidable terminator.) As usual, no English translation does Example 9.54 justice.

Note: Due to restrictions on the Lojban parsing algorithm, it is not possible to form modal connectives using the fi'o-plus-selbri form of modal. Only the predefined modals of selma'o BAI can be compounded as shown in Section 9.7 and Section 9.8.

Consider the example:

Example 9.55 has two modal sumti, using the modals bau and bai. Suppose we wanted to specify the language explicitly but be vague about who's doing the compelling. We can simplify Example 9.55 to:

In Example 9.56, the elidable terminator ku has taken the place of the sumti which would normally follow bai. Alternatively, we could specify the one who compels but keep the language vague:

We are also free to move the modal-plus- ku around the bridi:

An alternative to using ku is to place the modal cmavo right before the selbri, following the cu which often appears there. When a modal is present, the cu is almost never necessary.

In this use, the modal is like a tanru modifier semantically, although grammatically it is quite distinct. Example 9.59 is very similar in meaning to:

The se conversion is needed because bapli tavla would be a “compeller type of speaker” rather than a “compelled (by someone) type of speaker”, which is what a bai tavla is.

If the modal preceding a selbri is constructed using fi'o, then fe'u is required to prevent the main selbri and the modal selbri from colliding:

There are two other uses of modals. A modal can be attached to a pair of bridi-tails that have already been connected by a logical, non-logical, or modal connection (see Chapter 14 for more on logical and non-logical connections):

Here the bai is spread over both klama le zarci and cadzu le bisli, and the ge ... gi represents the logical connection “both-and” between the two.

Similarly, a modal can be attached to multiple sentences that have been combined with tu'e and tu'u, which are explained in more detail in Section 19.2:

means the same thing as Example 9.62.

Note: Either BAI modals or fi'o-plus-selbri modals may correctly be used in any of the constructions discussed in this section.

The following cmavo are discussed in this section:

Relative phrases and clauses are explained in much more detail in Chapter 8. However, there is a construction which combines a modal with a relative phrase which is relevant to this chapter. Consider the following examples of relative clauses:

In Example 9.64, la .apasionatas. refers to a particular performance of the sonata, namely the one performed by Rubinstein. Therefore, the relative clause poi se cusku uses the cmavo poi (of selma'o NOI) to restrict the meaning of la .apasionatas to the performance in question.

In Example 9.65, however, la .apasionatas. refers to the sonata as a whole, and the information that it was composed by Beethoven is merely incidental. The cmavo noi (also of selma'o NOI) expresses the incidental nature of this relationship.

The cmavo pe and ne (of selma'o GOI) are roughly equivalent to poi and noi respectively, but are followed by sumti rather than full bridi. We can abbreviate Example 9.64 and Example 9.65 to:

Here the precise selbri of the relative clauses is lost: all we can tell is that the Appassionata is connected in some way with Rubinstein (in Example 9.66) and Beethoven (in Example 9.67), and that the relationships are respectively restrictive and incidental.

It happens that both cusku and finti have BAI cmavo, namely cu'u and fi'e. We can recast Example 9.66 and Example 9.67 as:

Example 9.68 and Example 9.69 have the full semantic content of Example 9.64 and Example 9.65 respectively.

Modal relative phrases are often used with the BAI cmavo mau and me'a, which are based on the comparative gismu zmadu (more than) and mleca (less than) respectively. The place structures are:

Here are some examples:

Example 9.70 requires that Frank likes Betty, but adds the information that his liking for Betty exceeds his liking for Mary. The modal appears in the form semau because the x2 place of zmadu is the basis for comparison: in this case, Frank's liking for Mary.

Here we are told that Frank likes Mary less than he likes Betty; the information about the comparison is the same. It would be possible to rephrase Example 9.70 using me'a rather than semau, and Example 9.71 using mau rather than seme'a, but such usage would be unnecessarily confusing. Like many BAI cmavo, mau and me'a are more useful when converted with se.

If the ne were omitted in Example 9.70 and Example 9.71, the modal sumti (la meiris. and la betis. respectively) would become attached to the bridi as a whole, producing a very different translation. Example 9.71 would become:

which compares a liking with a person, and is therefore nonsense.

Pure comparison, which states only the comparative information but says nothing about whether Frank actually likes either Mary or Betty (he may like neither, but dislike Betty less), would be expressed differently, as:

The mechanisms explained in this section are appropriate to many modals other than semau and seme'a. Some other modals that are often associated with relative phrases are: seba'i (“instead of”), ci'u (“on scale”), de'i (“dated”), du'i (“as much as”). Some BAI tags can be used equally well in relative phrases or attached to bridi; others seem useful only attached to bridi. But it is also possible that the usefulness of particular BAI modals is an English-speaker bias, and that speakers of other languages may find other BAIs useful in divergent ways.

Note: The uses of modals discussed in this section are applicable both to BAI modals and to fi'o-plus-selbri modals.

It is possible to mix logical connection (explained in Chapter 14) with modal connection, in a way that simultaneously asserts the logical connection and the modal relationship. Consider the sentences:

which is a logical connection, and

The meanings of Example 9.74 and Example 9.75 can be simultaneously expressed by combining the two compound cmavo, thus:

Here the two sentences mi nelci do and mi nelci la djein. are simultaneously asserted, their logical connection is asserted, and their causal relationship is asserted. The logical connective je comes before the modal ki'u in all such mixed connections.

Since mi nelci do and mi nelci la djein. differ only in the final sumti, we can transform Example 9.76 into a mixed sumti connection:

Note that this connection is an afterthought one. Mixed connectives are always afterthought; forethought connectives must be either logical or modal.

There are numerous other afterthought logical and non-logical connectives that can have modal information planted within them. For example, a bridi-tail connected version of Example 9.77 would be:

The following three complex examples all mean the same thing.

In Example 9.79, the tu'e…tu'u brackets are the equivalent of the ke…ke'e brackets in Example 9.80 and Example 9.81, because ke…ke'e cannot extend across more than one sentence. It would also be possible to change the .ijeseri'abo to .ije seri'a, which would show that the tu'e…tu'u portion was an effect, but would not pin down the mi bevri le dakli portion as the cause. It is legal for a modal (or a tense; see Chapter 10) to modify the whole of a tu'e…tu'u construct.

Note: The uses of modals discussed in this section are applicable both to BAI modals and to fi'o-plus-selbri modals.

The following cmavo are discussed in this section:

So far, conversion of numbered bridi places with SE and the addition of modal places with BAI have been two entirely separate operations. However, it is possible to convert a selbri in such a way that, rather than exchanging two numbered places, a modal place is made into a numbered place. For example,

has an explicit x1 place occupied by mi and an explicit bau place occupied by la lojban. To exchange these two, we use a modal conversion operator consisting of jai (of selma'o JAI) followed by the modal cmavo. Thus, the modal conversion of Example 9.82 is:

In Example 9.83, the modal place la lojban. has become the x1 place of the new selbri jai bau cusku. What has happened to the old x1 place? There is no numbered place for it to move to, so it moves to a special “unnumbered place” marked by the tag fai of selma'o FA.

Note: For the purposes of place numbering, fai behaves like fi'a; it does not affect the numbering of the other places around it.

Like SE conversions, JAI conversions are especially convenient in descriptions. We may refer to “the language of an expression” as le jai bau cusku, for example.

In addition, it is grammatical to use jai without a following modal. This usage is not related to modals, but is explained here for completeness. The effect of jai by itself is to send the x1 place, which should be an abstraction, into the fai position, and to raise one of the sumti from the abstract sub-bridi into the x1 place of the main bridi. This feature is discussed in more detail in Section 11.10. The following two examples mean the same thing:

Example 9.85, with the bracketed part omitted, allows us to say that “I am justified” whereas in fact it is my action that is justified. This construction is vague, but useful in representing natural-language methods of expression.

Note: The uses of modals discussed in this section are applicable both to BAI modals and to fi'o-plus-selbri modals.

Negation is explained in detail in Chapter 15. There are two forms of negation in Lojban: contradictory and scalar negation. Contradictory negation expresses what is false, whereas scalar negation says that some alternative to what has been stated is true. A simple example is the difference between “John didn't go to Paris” (contradictory negation) and “John went to (somewhere) other than Paris” (scalar negation).

Contradictory negation involving BAI cmavo is performed by appending -nai (of selma'o NAI) to the BAI. A common use of modals with -nai is to deny a causal relationship:

Example 9.86 denies that the relationship between my liking you (which is asserted) and your liking me (which is not asserted) is one of motivation. Nothing is said about whether you like me or not, merely that that hypothetical liking is not the motivation for my liking you.

Scalar negation is achieved by prefixing na'e (of selma'o NAhE), or any of the other cmavo of NAhE, to the BAI cmavo.

Example 9.87 says that the relationship between the plant's growth and your watering it is not one of motivation: the plant is not motivated to grow, as plants are not something which can have motivation as a rule. Implicitly, some other relationship between watering and growth exists, but Example 9.87 doesn't say what it is (presumably ri'a).

Note: Modals made with fi'o plus a selbri cannot be negated directly. The selbri can itself be negated either with contradictory or with scalar negation, however.

The following cmavo is discussed in this section:

Like tenses, modals can be made persistent from the bridi in which they appear to all following bridi. The effect of this “stickiness” is to make the modal, along with its following sumti, act as if it appeared in every successive bridi. Stickiness is put into effect by following the modal (but not any following sumti) with the cmavo ki of selma'o KI. For example,

means the same as:

In Example 9.88, bai is made sticky, and so Frank's compelling is made applicable to every following bridi. bau is not sticky, and so the language may vary from bridi to bridi, and if not specified in a particular bridi, no assumption can safely be made about its value.

To cancel stickiness, use the form BAI ki ku, which stops any modal value for the specified BAI from being passed to the next bridi. To cancel stickiness for all modals simultaneously, and also for any sticky tenses that exist (ki is used for both modals and tenses), use ki by itself, either before the selbri or (in the form ki ku) anywhere in the bridi:

Note: Modals made with fi'o-plus-selbri cannot be made sticky. This is an unfortunate, but unavoidable, restriction.

Logical and non-logical connectives are explained in detail in Chapter 14. For the purposes of this chapter, it suffices to point out that a logical (or non-logical) connection between two bridi which differ only in a modal can be reduced to a single bridi with a connective between the modals. As a result, Example 9.91 and Example 9.92 mean the same thing:

Neither example implies whether a single act, or two acts, of running is referred to. To compel the sentence to refer to a single act of running, you can use the form:

The cmavo ce'e creates a termset containing two terms (termsets are explained in Chapter 14 and Chapter 16). When a termset contains more than one modal tag derived from a single BAI, the convention is that the two tags are derived from a common event.

There are 65 cmavo of selma'o BAI, of which all but one (do'e, discussed in Section 9.6), are derived directly from selected gismu. Of these 64 cmavo, 36 are entirely regular and have the form CV'V, where C is the first consonant of the corresponding gismu, and the Vs are the two vowels of the gismu. The remaining BAI cmavo, which are irregular in one way or another, are listed in the table below. The table is divided into sub-tables according to the nature of the exception; some cmavo appear in more than one sub-table, and are so noted.

The following table shows all the cmavo belonging to selma'o BAI, and has five columns. The first column is the cmavo itself; the second column is the gismu linked to it. The third column gives an English phrase which indicates the meaning of the cmavo; and the fourth column indicates its meaning when preceded by se.

For those cmavo with meaningful te, ve, and even xe conversions (depending on the number of places of the underlying gismu), the meanings of these are shown on one or two extra rows following the primary row for that cmavo.

It should be emphasized that the place structures of the gismu control the meanings of the BAI cmavo. The English phrases shown here are only suggestive, and are often too broad or too narrow to correctly specify what the acceptable range of uses for the modal tag are.

The lujvo tamsmi on which tai is based is derived from the tanru tarmi simsa and has the place structure:

This lujvo is employed because tarmi does not have a place structure useful for the modal's purpose.