People constructing lujvo usually want them to be as short as possible. To that end, they will discard any cmavo they regard as niceties. The first such cmavo to get thrown out are usually ke and ke'e, the cmavo used to structure and group tanru. We can usually get away with this, because the interpretation of the tertau with ke and ke'e missing is less plausible than that with the cmavo inserted, or because the distinction isn't really important.

For example, in bakrecpa'o, meaning “beefsteak”, the veljvo is

because of the usual Lojban left-grouping rule. But there doesn't seem to be much difference between that veljvo and

On the other hand, the lujvo zernerkla, meaning “to sneak in”, almost certainly was formed from the veljvo

because the alternative,

doesn't make much sense. (To go to the inside of a crime? To go into a place where it is criminal to be inside – an interpretation almost identical with Example 12.51 anyway?)

There are cases, however, where omitting a KE or KEhE rafsi can produce another lujvo, equally useful. For example, xaskemcakcurnu means “oceanic shellfish”, and has the veljvo

(“worm” in Lojban refers to any invertebrate), but xasycakcurnu has the veljvo

and might refer to the parasitic worms that infest clamshells.

Such misinterpretation is more likely than not in a lujvo starting with sel- (from se), nal- (from na'e) or tol- (from to'e): the scope of the rafsi will likeliest be presumed to be as narrow as possible, since all of these cmavo normally bind only to the following brivla or ke…ke'e group. For that reason, if we want to modify an entire lujvo by putting se, na'e or to'e before it, it's better to leave the result as two words, or else to insert ke, than to just stick the SE or NAhE rafsi on.

It is all right to replace the phrase se klama with selkla, and the places of selkla are exactly those of se klama. But consider the related lujvo dzukla, meaning “to walk to somewhere”. It is a symmmetrical lujvo, derived from the veljvo cadzu klama as follows:

We can swap the k1 and k2 places using se dzukla, but we cannot directly make se dzukla into seldzukla, which would represent the veljvo selcadzu klama and plausibly mean something like “to go to a walking surface”. Instead, we would need selkemdzukla, with an explicit rafsi for ke. Similarly, nalbrablo (from na'e barda bloti) means “non-big boat”, whereas na'e brablo means “other than a big boat”.

If the lujvo we want to modify with SE has a seltau already starting with a SE rafsi, we can take a shortcut. For instance, gekmau means “happier than”, while selgekmau means “making people happier than, more enjoyable than, more of a 'se gleki' than”. If something is less enjoyable than something else, we can say it is se selgekmau.

But we can also say it is selselgekmau. Two se cmavo in a row cancel each other (se se gleki means the same as just gleki), so there would be no good reason to have selsel in a lujvo with that meaning. Instead, we can feel free to interpret selsel- as selkemsel-. The rafsi combinations terter-, velvel- and xelxel- work in the same way.

Other SE combinations like selter-, although they might conceivably mean se te, more than likely should be interpreted in the same way, namely as se ke te, since there is no need to re-order places in the way that se te provides. (See Section 9.4.)