• Intransitive S_P: There are many intransitive S_P roots. Intransitive S_P stems may be derived only from noun roots plus intransitive verbalizing suffixes.
• Transitive: There are many transitive roots. Transitive stems are derived from noun roots plus transitive verbalizing suffixes, or from intransitive S_P stems plus one of 2-4 transitivizing (distinct from causative) suffixes.
• Ditransitive: There are only two or three ditransitive roots, verbs meaning ‘give’, ‘present’ and ‘put’. Ditransitive stems are productively derived from transitive stems plus a causative suffix.
• Intransitive S_A: There are usually fewer than 10 Intransitive S_A roots. Intransitive S_A stems are derived from transitive stems or ditransitive stems by the addition of a detransitivizing prefix.

Intransitive S_A stems behave crosslinguistically like “middle” verbs: semantics can be reflexive, reciprocal, anticausative, passive, antipassive, idiosyncratic (i.e. not predictable from meaning of the transitive verb) and sometimes deponent (no transitive verb identifiable).

There are also a few meaning-changing derivational suffixes, usually coding aspect: most common are the completive (to completely finish) and iterative ‘do multiple times’, but some languages (e.g. Makushi) have innovated others, like inchoative (begin), terminative (stop, finish), conative (try unsuccessfully) and ‘finally’.