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
11.1) [ke] bakni rectu [ke'e] panlo
( bovine meat ) slice
because of the usual Lojban left-grouping rule. But there doesn’t seem to be much difference between that veljvo and
11.2) bakni ke rectu panlo [ke'e]
bovine ( meat slice )
On the other hand, the lujvo “zernerkla”, meaning “to sneak in”, almost certainly was formed from the veljvo
11.3) zekri ke nenri klama [ke'e]
crime ( inside go )
to go within, criminally
because the alternative,
11.4) [ke] zekri nenri [ke'e] klama
(crime inside) go
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 11.3 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
11.5) xamsi ke calku curnu
ocean type-of (shell worm)
(“worm” in Lojban refers to any invertebrate), but “xasycakcurnu” has the veljvo
11.6) [ke] xamsi calku [ke'e] curnu
(ocean shell) type-of worm
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:
11.7) “cadzu”: c1 walks on surface c2 using limbs c3
“klama”: k1 goes to k2 from k3 via route k4 using k5
“dzukla”: c1=k1 walks to k2 from k3 via route k4 using limbs k5=c3
on surface c2
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 Chapter 9.)