The prefixes and suffixes (apart from those used with numerals) of the reconstructed TB speech are listed below. In modern TB languages the prefixes normally have reduced stress and the neutral ∂ type of vocalization. Thus, the form written *g- is to be interpreted as *g∂ (with ∂ as a separate phoneme) or as gǎ (with ǎ an allophone of the phoneme /a/ in syllables with reduced stress). The vowel of the prefix is affected by vocalic harmony in several groups, notably Bodo-Garo and Mikir; cf. Dimasa gabaŋ ‘much’, gosoŋ ‘steep’, gusum ‘blue’, gepher ‘flat’, gimin ‘ripe’.

1. Suffixed *-s: original function uncertain; often reflexive in verb roots.

2. Suffixed *-t and *-n: original function uncertain; sometimes used in deriving nouns from verb roots; also causative or directive.

3. Prefixed *s-: causative, directive, or intensive with verb roots; often stands for TB *sya ‘flesh; animal’ in noun roots.

4. Prefixed *r-: both in verb and noun roots; function unknown.

5. Prefixed *b-: perhaps pronominal in some roots, but function generally unknown.

6. Prefixed *g-: rare; function unknown.

7. Prefixed *d-: rare; function unknown.

8. Prefixed *m-: pronominal in noun roots; intransitive in verb roots.