Mama alimwona mende mmoja karibu na sinki jana usiku.

It can be broken down as:

• a- = he/she
• -li- = past tense
• -mw- = him/her/it as an object marker for a singular animate being
• -ona = see

So alimwona means he/she saw him/her/it. In this sentence, the subject is Mama, so it means Mom/Mother saw it.

In Swahili, the object can be marked twice:

• once inside the verb with an object marker
• and again as a full noun after the verb

This is especially common when the object is animate or specific. So alimwona mende mmoja is perfectly natural.

You may also hear Mama aliona mende mmoja... without the object marker. That is also possible, but alimwona makes the object feel more clearly identified in the sentence.

Because mende is a living creature. In Swahili, many animal nouns often behave like animate nouns for agreement purposes, even if their noun class is not the usual human class.

That is why you get forms like:

• alimwona rather than a non-animate-style object marker
• mmoja rather than a non-animate agreement form

For learners, the useful rule is: animals often trigger animate agreement.

Because in Swahili, the noun usually comes first, and words that describe or limit it come after it.

So:

• mende mmoja = one cockroach
• literally, cockroach one

This is normal Swahili word order for numbers and many modifiers.

The word for one changes to agree with the noun. With animate nouns, it often appears as mmoja.

So here:

• mende mmoja = one cockroach

This matches the animate pattern that is also seen in the verb.

karibu na means near, close to, or next to.

So:

• karibu na sinki = near the sink

The na is normally used when karibu is followed by a noun. On its own, karibu can also have other meanings, such as welcome.

It is a loanword from English sink.

That is very common in Swahili, especially for modern objects and household items. So sinki is a normal word to use in everyday Swahili.

Literally, jana usiku means yesterday night.

Idiomatic English translates that as last night. Yes, this is a normal and common way to express that idea in Swahili.

You may also hear:

• usiku wa jana = the night of yesterday / last night

Both are understandable and natural.

Because Swahili does not use articles like English a, an, and the.

Instead, definiteness is usually understood from:

• context
• word order
• demonstratives
• numerals
• object marking

So mende mmoja can mean one cockroach, and in context it may naturally be understood as a cockroach. Likewise, sinki can mean the sink if the context makes it clear which sink is meant.

The given sentence has a very natural neutral order:

• Subject: Mama
• Verb: alimwona
• Object: mende mmoja
• Place: karibu na sinki
• Time: jana usiku

But Swahili word order is somewhat flexible. For example, you could also say:

• Jana usiku, Mama alimwona mende mmoja karibu na sinki.

That puts more emphasis on last night. So the original order is natural, but it is not the only possible order.

Literally, mama means mother or mom.

Depending on context, Mama can also be used as a respectful way to refer to or address a woman. In this sentence, though, the most natural reading is simply Mom or Mother.