Thematic Suffix
The language has eight kinds of thematic suffixes (also sometimes known as present-future stem formants or PFSF). When the suffixal passive marker is absent, one of these suffixes can be placed right after the root of the verb. With these suffixes the verbs gain arbitrary meanings. Thematic suffixes are present in the present and future screeves, but are absent in the past and mostly absent in the perfective screeves. For example, the root of the verb "build" is -shen-. In order to say "I am building", we have to add the thematic suffix -eb- to the end of the root: v-a-shen-eb (v- meaning that the doer is the first person (v- set nominal marker), a is the versioner, shen is the root, and eb is the thematic suffix). To say "he/she is building", we simply add the suffixal nominal marker -s after the thematic suffix: a-shen-eb-s.
Read more about this topic: Georgian Grammar, Verbal System, Verb Components