Verb extensions in Kah consist of prefixed verbs altering the meaning of the verb they are attached to. This means that a single verb stem can be used to built new verbs from in a standardized manner. This method has proved to be a rich source of verbal derivation in many natural and constructed languages. For constructed languages the main benefit lies in the instant recognizability and logic it adds to the lexicon as well as the fact it keeps the minimum number of roots needed for a mature lexicon beneath acceptable perimeters.
The phonotactic rules of verb extensions differ slightly from those of normal compounds. When a common verbal derivational prefix ending in a nasal stop (either -m, -n or -ng) is put in front of f, v,h, l, r, a consonant combination (kw, sw and py) or another nasal stop, the final nasal is dropped:
jam + le = jale (and not: *jamale)
mun + ren = muren (and not: *munuren)
tom + reven = toreven (and not: *tomoreven)
The reversive extensions expressed the undoing of an action and is formed by prefixing the verb mon "to undo" to the original verb. Compare:
to be stable
to wake up
Permissive verbs are formed with the root ten- expressing "to be able" and express something rather hard to describe. It denotes that an action or quality is possible, advisory or morally right.
to be visible
to be predictable
to be explosive
A causative verbs express an action is caused to happen. The verb mun "to cause" is prefixed to the basic verb stem:
to halt, make stop
to play a song
to inflict pain, hurt