In the last few months I have been focusing almost entirely on Kahtsaai vocabulary, and allowing that to drive any tweaks to the grammar. At this point, I consider the skeleton of the grammar complete, wanting only a lot more detail for certain sections.
For most of its life Kahtsaai has had a single primary verb of motion, ló, which was usually marked with either the trans- or cis-locative prefix to distinguish go and come. This turns out to be typologically very rare, which was fine, but I finally started to find it annoying, so I added aas come. The form kóh-ló is still available for come, but it cannot be used when the speaker means "right here where we're talking now," which is aas's core meaning.
At the same time aas was coming into being, I was getting a bit annoyed about the regularity of the imperfective marker, -na. I did not want to add massive irregularity, but it just wasn't sitting right all by itself. So, I added a small number of verbs which take the imperfective in -rá/-réí. The choice between the two forms depends on things like stem syllable weight and compensatory lengthening after certain assimilations, but for practical purposes should be considered irregular. In a last act of randomness, I seriously modified aas, giving it an imperfective of saréí. Finally, an imperfective in -rá becomes -réí when the adverbial suffix -ne/-hte is added, always resulting in -réín. This parallels the -na > -naan change.
I have confined the -rá/-réí forms to intransitive verbs of motion ("come," "flow"), location and posture ("stand," "hang") and weather ("lightening"). I don't expect that to change. Right now only thirteen verbs have this new imperfective. Probably a few more will enter this class over time, but I doubt it will be too many.
Postpositions and Verbs do the Frame Dance
I recently added the postposition -próh. It is imagined that at one point in its history it covered certain meanings one expects of the dative, but by about, say, a half a millennium ago it was confined to marking the experiencer of certain verbs of emotion or judgement. For example, léíkou means insipid, flavorless, boring. With -próh one can say someone is bored,
Ra'é tápróh heléíkou. ra'é tá-próh he-léíkou that.INAN 1SG-to 3INAN-be.insipid That bores me.
The postposition now also marks the judicantis role, that is, the person in whose judgement a statement holds true.
Táttá aapróh máámo łakíntsááłtsi wé. tá-ttá aa-próh máámo ła-kí-n-tsááł-ts wé 1SG-father 3AN.SG-to money TRNS-3INAN.S-3INAN-misuse-EVID this To my father, this is a waste of money.
In thinking about the core uses for -próh an interesting commonality has developed, where a stative verb takes the "detransitive of causative" marking -ríi-se and is then used with -próh to mark the induction of some state in a person. For example, láhme means "be angry, be unpleasant," but rather than taking the causative for "to anger," instead this -ríi-se form is used, tápróh yoláhmeríise he made me angry. I'm expecting to see more of the construction X-próh Vstative-ríi-se in the future.
Finally, I have started thinking more about the frames of new and existing vocabulary, and making sure I have examples covering expected uses. One result of this is that the postposition -por, "seeking after, wanting," is now used mark the ultimate goal for purposive action. For example, the verb móka means "trick" or "deceive." The postposition -por marks the goal of the deception if that is expressed,
Yokatmókats máámo onpor pá. yo-kat-móka-ts máámo on-por pá 3AN.SG-1PL-trick-EVID money 3INAN-wanting PTCL He tricked us for the money.
This week makes me want to give into the "40 words for snow" syndrome, and create a rich vocabulary to describe my own emotional state when experiencing 95-100F days and very high humidity. I'm also trying to think up a good way to express "at stake, on the line," as in the phrase, "when your life is at stake." This is a subtle one.