hatu-

The prefix hatu- is formed by attaching the negative prefix ha- directly to the subject prefix tu-. It is the standard way to express "we do not" or "we are not" (doing an action) in the present tense. Note that it cannot be used to say "we are not" followed by a noun or adjective (like "we are not teachers"); for that, you must use the negative copula si.

Key Rules for Forming the Present Negative:

• Drop the tense marker: The -na- completely disappears. This also applies to the indefinite present tense marker -a- (e.g., both tunasoma and twasoma become hatusomi).
• Change the final vowel: For verbs of Bantu origin ending in -a, the final vowel changes to -i (e.g., tunasoma [we read] → hatusomi [we do not read]).
• Loanword exemption: Verbs of Arabic origin ending in -e, -i, -u, or -au do not change their final vowel (e.g., tunajibu [we answer] → hatujibu [we do not answer], tunasahau [we forget] → hatusahau [we do not forget]).
• Monosyllabic and vowel-commencing verbs: Short verbs drop their infinitive ku- prefix (e.g., tunakula [we eat] → hatuli [we do not eat], and tunakunywa [we drink] → hatunywi). For vowel-commencing verbs like kwenda (to go), the kw- is just the infinitive prefix reacting to a vowel, so it also drops (e.g., tunakwenda → hatuendi).
• Object markers: Inserting an object marker between the tense/subject markers and the verb root does not change these negative rules (e.g., tunakisoma [we read it] → hatukisomi [we do not read it]).
• The verb 'to have': When negating kuwa na (to have), tuna [we have] becomes hatuna [we do not have] by simply adding the ha- prefix. It does not change the final -a to -i.

Because hatu- already means "we," adding the pronoun sisi is only necessary if you want to emphasize "We do not... (but someone else might)."

Meaning and the Special Have Form:
Hatusomi can mean “we are not reading” now or “we do not read” habitually; context chooses the English tense. Hatuna is ha-tu-na (we do not have), a negative subject plus the special na construction. Its final a is part of na, so it does not undergo the ordinary a-final verb’s present-negative -i change.