Negation of the Verbs ‘To Be,’ and ‘To Have’

The verb kuwa means “to be” or “to become,” the verb kuwa na means “to have” or “to be with”. All of these verbs are derived from the monosyllabic verb wa which means “be.”
Since these verbs are derived from a monosyllabic verb. Kuwa and kuwa na can be used with all tenses, however, in the present tense, they take irregular forms. In the present tense, the verb kuwa becomes ni, the and verb kuwa na becomes –na.

Kuwa (to be or to become)
The verb kuwa means “to be” or “to become.” As you may recall, verbs are used in the following structure in a simple sentence:
Subject prefix + Tense marker + Verb
The following are a few examples of sentences using kuwa in the simple past, past perfect and future tenses.
Alikuwa hodari. – He/She was clever.
Wamekuwa matajiri. – They have become wealthy people.
Nitakuwa mwalimu. – I will become a teacher.

Negation of Kuwa

The above sentences are negated as follows:
Hakuwa hodari. – He/She was not clever.
Hawajakuwa matajiri. – They have not yet become wealthy people.
Sitakuwa mwalimu. – I will not become a teacher.
When we use kuwa in the present tense, the verb kuwa is substituted by ni. In this context the word ni is translated as “am,” “is” or “are” and carries the meaning of “be.” It should not be confused with the subject prefix ni- which translates as “I.”

Subject prefix + Tense marker + Irregular form of the Verb (ni)
The following are a few examples of sentences using ni.
Baba yake ni mhasibu. – His/her father is an accountant.
Sahani hizi ni ghali. – These plates are expensive.
Maembe yale ni mabivu. – Those mangoes are ripe.
In order to negate sentences using ni in the present tense, the verb ni is replaced by its negative form, which is si and is translated as “am not,” “is not” or “are not” and carries the meaning of “not to be.”
Therefore, the above sentences are negated as follows:
Baba yake si mhasibu. – His/her father is not an accountant.
Sahani hizi si ghali. – These plates are not expensive.
Maembe yale si mabivu. – Those mangoes are not ripe.

Kuwa na (to have or to be with)
The verb kuwa na means “to have” or “to be with.” As you may recall from, verbs are used in the following structure in a simple sentence:
Subject prefix + Tense marker + Verb
The following are a few examples of sentences using kuwa na in the simple past, past perfect and future tenses.
Nilikuwa na watoto wangu. – I was with my children.
Watakuwa na gari kesho kutwa. – They will have a car the day after tomorrow.
Mmekuwa na bahati nzuri. – You (pl.) have had good luck.
Palikuwa na wadudu wengi. – The place (definite) had many insects.
The above sentences are negated as follows:

Sikuwa na watoto wangu. – I was not with my children.
Hawatakuwa na gari kesho kutwa. – They will not have a car the day after tomorrow.
Hamjakuwa na bahati nzuri. – You (pl.) have not yet had good luck.
Hapakuwa na wadudu wengi. – The place (definite) did not have many insects.

When we use kuwa na in the present tense, the verb kuwa na is substituted by -na. In this context, the word -na still carries the meaning of “have” and it should not be confused with -na which is used to construct reciprocal verbs.

Subject prefix + Tense marker + Irregular form of the Verb (-na)
The following are a few examples of sentences using -na:

Kiti hiki kina rangi nyekundu. – This chair has a red colour. (This chair is red).
Wana mboga za aina nyingi sokoni. – They have many kinds of vegetables in the market.
Seremala ana wateja wapya. – The carpenter has new customers.

As you can see in the sentences above, the present tense is implied and therefore, the present tense marker -na- is omitted.
The above sentences are negated as follows:

Kiti hiki hakina rangi nyekundu. – This chair does not have a red colour. (This chair is not red).
Hawana mboga za aina nyingi sokoni. – They do not have many kinds of vegetables in the market.
Seremala hana wateja wapya. – The carpenter does not have new customers.