It is absolutely unavoidable with an invented language that one cannot predict in advance exactly which words and locutions will see the most frequent usage. There is a universal desire among speakers for concision, for frequency to correlate with brevity. Inevitably, we are going to find that certain phrases are annoyingly syllableful relative to the frequency with which we want to say them.
Partly this problem could be done by simply reassigning the forms of short but largely unused cmavo, and assigning those short forms to currently-longer high-frequency cmavo. E.g. lau might become lau'au and du'u might become lau (though presumably du'u itself would remain valid).
But such reassignments would not make great inroads into the problem. A more radical solution would be to make certain cmavo rewrite as a string of more than one word at the preparser stage. For example it is proposed that xoi could rewrite at the preparser stage as lo'edu'u. Some sort of statistical calculation could be performed on a large body of mature usage in order to ascertain what sort of string substitutions would yield the greatest gain in terms of concision.
An advantage of this strategy is that the syntax proper would not have to be altered. For example, if it turned out that great gains could be had from having a short cmavo that rewrites as cu ja'a, it would not be necessary to attempt to perform the impossible task of trying to create a selmaho that can combine the syntactic functions of CU and NA.
rant about "exploiting the preparser" — moved to separate page.