Usiache chakula wazi mezani, kwa sababu panya na nzi wanaweza kukaribia usiku.

Usiache is a negative command: don’t leave.

It is built like this:

• u- = you (singular)
• -si- = negative marker
• -ach- = verb root from kuacha (to leave)
• -e = subjunctive ending

So u-si-ach-e literally gives the idea you should not leave → don’t leave.

By contrast, acha is the positive singular command: leave!

That -e is very important. In Swahili, negative commands usually use the subjunctive form of the verb.

So:

• kuacha = to leave
• acha! = leave!
• usiache! = don’t leave!

A learner coming from English often expects just a negative word plus the normal verb, but Swahili changes the verb form too. That is why you see usiache, not usiacha.

Swahili usually does not use articles like English the or a/an.

So chakula can mean:

• food
• the food
• some food

The exact sense comes from context.

In this sentence, the meaning is understood from the situation: it refers to food in general, or the food being talked about, without needing a separate article.

Here wazi means something like open, uncovered, or left exposed.

So chakula wazi means food left open/uncovered.

A useful point for learners: wazi is often used as an invariable adjective/adverb-like word, so it does not change to match the noun class the way many other adjectives do. That is why it stays wazi, not something like kiwazi.

Mezani comes from:

• meza = table
• -ni = locative ending

So mezani means on the table, at the table, or on/at the table area, depending on context.

This is very common in Swahili: instead of always using separate prepositions like English does, Swahili often adds -ni to a noun to make it locative.

Examples:

• nyumbani = at home
• shuleni = at school
• mezani = on/at the table

Kwa sababu is the normal Swahili way to say because.

Even though kwa by itself can mean things like by, with, for, or at, the combination kwa sababu works as a fixed expression meaning because.

A related expression is:

• kwa sababu ya ... = because of ...

So:

• kwa sababu panya na nzi... = because rats and flies...
• kwa sababu ya mvua = because of the rain

This is a very good question, because English speakers often expect non-human nouns to behave differently.

Panya (rats/mice) and nzi (flies) belong to noun classes that are not the human class, but in real Swahili, animals and other living creatures are often treated with animate agreement, especially in everyday usage.

So wanaweza here is natural:

• wa- = plural animate subject agreement
• -na- = present tense
• -weza = be able

So wanaweza = they can / they are able to

A learner might expect zinaweza, based on noun class logic, but wa- with animals is very common and idiomatic.

Because Swahili expresses can with a conjugated verb plus an infinitive.

• wanaweza = they can
• kukaribia = to approach / to come near

Together:

• wanaweza kukaribia = they can approach / they may come near

This works much like English:

• they can come
• they can approach

The first verb carries the subject and tense, and the second stays in the infinitive form.

Usiku means night or at night, depending on context.

In this sentence it is being used adverbially, so it means at night or during the night.

Swahili often uses time words without a preposition where English would need one. So:

• usiku = at night
• asubuhi = in the morning
• mchana = in the daytime
• leo = today
• kesho = tomorrow

So kukaribia usiku naturally means come near at night.

Yes, that can be confusing. In Swahili, many class 9/10 nouns have the same form in singular and plural.

So:

• panya can mean rat/mouse or rats/mice
• nzi can mean fly or flies

You usually tell from context, agreement, or the overall meaning.

In this sentence, the idea is clearly plural because:

• the animals are being mentioned generally
• they are joined by na (and)
• the verb is plural: wanaweza

So here the meaning is rats and flies.