All structures in this section apply to sumti at the main level of a sentence, as well as to sumti within substructures.
The modal tags, or sumti tcita, specify relationships such as time or location: e.g. pu 'before', ba 'after', ca 'simultaneous with', vi 'at', va 'near', vu 'far from'
There are many more of these, and some specialized rules for compounding them. These are discussed in the reference grammar.
| mi | [cu] | tavla |
| -- |
| pu | le nu do [cu] tavla [vau] [kei] [ku] | [vau] |
| PAST | ||
| mi tavla pu lenu do tavla | ||
| I talk before the-act-of you talk. | ||
| I talk before you do. | ||
Modal tags proper can also be used to add new sumti places to a selbri: e.g. secau (without ...), mu'i (motivational because ...), du'o (according to ...)
These express common English questions using time, location, and modal tag words combined with ma:
(Lojban has other 'because' modal tags for asking a variety of different 'why?' questions.)A sumti may be identified more exactly by attaching a relative phrase, another sumti, that in some way restricts the possible set of things being referred to:
pe, the basic marker of a restrictive relative phrase, is vague as to the exact nature of the relationship between the original sumti and the sumti that it is identifying. It is thus similar to the loosest English possessive, as in my chair/a chair of mine, which may for instance be used for a chair that you sit in but which is owned by someone else.
Successively tighter degrees of association/possession are indicated by po (alienable possession) and po'e (inalienable possession):
| le cukta [ku] | po | mi | [ge'u] |
| OF | |||
| The book of mine. (Even if you are holding it, it is still my book. But I also could give it to you, making it no longer my book.) | |||
| le birka [ku] | po'e | mi | [ge'u] |
| OF | |||
| The arm of mine. (It is intrinsically my arm; it cannot be given away, even if cut off.) | |||
po'u restricts a sumti by giving another identity: a sumti that could equivalently replace the original:
| la djan. | po'u | le vecnu [ku] | [ge'u] |
| OF | |||
| John | who-is | the seller | |
| -- | |||
| cu | klama | [vau] |
| goes. | ||
| John-the-salesman goes. | ||
goi, used like pe, defines ko'a and other variable sumti for use throughout a text without repeating:
| .i ko'a djica lenu do klama ko'a [vau] [kei] [ku] [vau] |
| He/she (the beautiful talker) wants the event of you going to him/her. |
Lojban has words identical in grammar to pe that provide non-restrictive (incidental) information about a sumti. ne is the non-restrictive (incidental) equivalent of pe.
This construct may be combined with the modal construct discussed just previously to identify a sumti:
| la djan. | ne | pu | la mark. | [ge'u] |
| PAST | ||||
| OF | ||||
| -- | ||||
| [cu] | melbi tavla | [vau] |
| John, who was (incidentally) before Mark, is a beautiful-talker. | ||
The contrast between ne (incidental) and pe (identifying) is shown by giving the same sentence with pe:
| la djan. | pe | pu | la mark. | [ge'u] |
| PAST | ||||
| OF | ||||
| -- | ||||
| [cu] | melbi tavla | [vau] |
| (The) John who was before Mark is a beautiful-talker. | ||
Certain modal tags, in fact, are designed primarily for use in relative phrases, rather than to attach additional sumti to the main bridi relationship as described earlier. One of these is semau ('more than ...'):
| la djan. | ne | semau | la mark. | [ge'u] |
| MORE THAN | ||||
| OF | ||||
| -- | ||||
| [cu] | tavla | mi | [vau] |
| John, (incidentally) more than Mark, talks to me. | |||
| John talks to me more than Mark does. | |||
| la djan. | [cu] | tavla |
| -- |
| mi | ne | semau | la mark. | [ge'u] | [vau] |
| PAST | |||||
| OF | |||||
| John talks to me, (incidentally) more than Mark. | |||||
| John talks to me more than he does to Mark. | |||||
| ???la djan. | [cu] | tavla | mi |
| -- |
| semau | la mark. | [vau] |
| MORE THAN | ||
| John talks to me, more than Mark. (but Mark is bound neither to John nor me, but to the talking). | ||
| (John's talking to me) is more than (Mark). | ||
pe-phrases are limited to what can be expressed in a single sumti. When you need to include more complete information about a sumti, Lojban provides for relative clauses. A restrictive relative clause marker, poi, marks a following complete bridi as information that identifies the sumti by providing a relationship that the sumti fits into.
The placeholder for the sumti being identified is ke'a, which is merely another in the set of single-word sumti. ke'a is often left out if it is contextually obvious where it would go (especially when ke'a would go in the x1 position immediately after poi, or in the first available unspecified place if x1 is already filled). A relative clause is terminated with the marker ku'o, which may be omitted if no ambiguity will result. It is very rare that ku'o needs to be expressed overtly.
| le ckule [ku] |
| The school |
| -- |
| poi | mi | [cu] | klama | ke'a | [vau] | [ku'o] |
| REL | ||||||
| which | I | go-to | it | |||
| -- | ||||||
| cu | blari'o | [vau] |
| is-blue-green | ||
| The school I go to is blue-green. | ||
| le bajra [ku] | poi | [ke'a] [cu] tavla [vau] [ku'o] |
| REL | ||
| -- | ||
| cu | vecnu | [vau] |
| le bajra poi tavla cu vecnu | ||
| The runner who talks is a seller. | ||
There is also a non-restrictive relative clause marker, noi, for incidental information about a sumti.
A sumti may also have a time or location or modal tag placed in front of its description selbri:
A description sumti can also have a sumti after the le but before the selbri, resulting in an abbreviated form of the loose pe possessive:
This sentence is completely equivalent to:A more complete structure of a description sumti is "[number] le [number] [sumti] [modal] selbri [ku]".
Immediately after cu and before a selbri, you can have a modal. (The modal being there may make cu redundant, since modals cannot be absorbed into tanru, so they cannot be conflated with the selbriitself.) Such modals serve as an equivalent to English tenses and adverbs. In Lojban, tense is completely optional. If unspecified, tense is picked up from context.
A variety of constructs may occur anywhere in a sentence, operating independent of the primary grammar of the sentence. These constructs generally have minimal internal grammar. Like xu, when they are not at the beginning of a sentence, they indicate emphasis on the word or construct that they immediately follow.
Attitudinals include a variety of expressions conveyed in English through interjections or tone of voice. Lojban supports an enormous range of emotional expression through specific words and compounds. Indicators may be modified for intensity, or classified by the sphere that they apply to (social, mental, emotional, physical, sexual, spiritual).
Discursives allow free expression of certain metalinguistic comments (comments about the text). Use of discursives allows clear separation of these metalinguistic features from the underlying statements and logical structure. By comparison, the English words but and also, which discursively indicate contrast or added weight-of-example, are logically equivalent to and without that discursive content. The average English speaker does not think about, and may not even realize, the contrary-seeming idea that but basically means and.
Evidentials indicate the speaker's relationship to the statement, specifically communicating what kind of knowledge the speaker is basing the statement on. These include za'a ("I directly observe the relationship"), pe'i ("I opine that the relationship holds") ru'a ("I postulate"), and others. Many Native American languages use these type of words.
Some expressions overlap between categories, behaving as indicators as well as evidentials (.ia, belief, faith), or attitudinals/discursives (ga'i, hauteur, relative high-rank; cf. Japanese).