[Grammar] Reversive forms

-ul-, -un-, -uk-

The verb formed with the radical plus the above suffixes indicates an opposite action to the one described with the initial verb. There exist two forms of reversive suffixes: active and passive.

Reversive active suffixes: -ul-, -un-

Verbs thus formed are transitive. They need an object.

Examples:

• kukànga (fermer, to close) → kukangula (ouvrir, to open)
• kuvwàla (vêtir, to put clothes on) → kuvùùla (dévêtir, to put clothes off)
• kulamika (coller, attacher, to glue, to attach) → kulamuna (détacher, to detach)

Reversive passive suffix : -uk-

Verbs including this suffix are intransitive and imply a state or a condition in which the subject sustains an opposite action.

Examples:

• kukanga (fermer, to close) → kukanguka (s’ouvrir, to be opened)
• kubutula (exterminer, exterminate) → kubutuka (se faire exterminer , to be exterminated)
• kupapula (effrayer, to frighten) → kupapuka (s’effrayer, to be frightened)
• kwambula (porter, to lift up) → kwambuka (se faire porter, to be lifted)

Source: CRIC