Mama hatumii mafuta mengi; wakati mwingine hutumia samli kidogo tu kupika chapati.

Because Mama is treated as a singular human noun, so it takes class 1 subject agreement.

With this verb:

• affirmative would be anatumia = she uses / she is using
• negative becomes hatumii = she does not use

So even though mama does not visibly look like a class 1 noun, it still behaves like one grammatically because it refers to a person.

In the negative present, Swahili verbs normally change the final -a to -i.

So:

• kutumia → anatumia in the affirmative
• kutumia → hatumii in the negative

The verb -tumia already has an i before the final vowel, so when the final -a changes to -i, you get -ii:

• tumia → tumii

That is why hatumii looks a little unusual at first.

They are different verb forms:

• hatumii = she does not use
• hutumia = she uses / she tends to use / she sometimes uses

The form hu- often gives a habitual or general meaning. It is very natural with expressions like wakati mwingine = sometimes.

So the sentence is contrasting:

• generally, she does not use much oil
• but sometimes, she does use a little ghee

The hu- habitual form often appears without a separate subject marker. The subject is understood from context.

Here, the sentence starts with Mama, and the second clause continues talking about the same person:

• Mama hatumii mafuta mengi
• wakati mwingine hutumia...

So hutumia is understood as Mama hutumia = Mama uses / she uses.

Because mafuta belongs to class 6 in Swahili, and adjectives must agree with the noun class.

The adjective stem is -ingi = many / much, and with class 6 it becomes:

• mengi

So:

• mafuta mengi = much oil / a lot of oil

Even though mafuta is grammatically plural in form, in English it is often translated as an uncountable noun: oil, not necessarily oils.

Because mafuta is often used as a mass noun in Swahili, even though its grammar looks plural.

So in real usage:

• mafuta mengi usually means a lot of oil
• not necessarily many different oils

This is one of those places where Swahili grammar and English translation do not line up word-for-word.

Here kidogo means a little / a small amount, not literally small in the ordinary descriptive sense.

So:

• samli kidogo = a little ghee
• samli kidogo tu = just a little ghee

This kidogo is very common with mass nouns and quantities. It functions more like an amount expression than a normal size adjective.

The word tu adds emphasis:

• tu = only / just

So kidogo tu means just a little.

Literally, wakati mwingine is something like another time or at another time, but very often it means:

• sometimes
• at times
• occasionally

It is a very common expression in everyday Swahili.

Kupika is the infinitive to cook / to prepare / to make. Here it shows purpose.

So:

• hutumia samli kidogo tu kupika chapati = she uses just a little ghee to cook/make chapati

In other words, the ghee is used for cooking chapati.

In everyday Swahili, chapati is often used as a loanword whose form may stay the same in singular and plural.

So depending on context, it can mean:

• chapati
• chapatis
• or chapati in general

In this sentence, the exact number is not the main point. The idea is simply that the ghee is used for making chapati.

Because in Swahili, adjectives and quantity words usually come after the noun they describe.

So the normal order is:

• noun + adjective/quantity

Examples:

• mafuta mengi = much oil
• samli kidogo = a little ghee

This is the regular Swahili pattern, even though English often uses a different order.