Mwalimu alisema kila sentensi iishie kwa nukta.

A simple breakdown is:

Mwalimu = teacher
alisema = said
kila = every
sentensi = sentence
iishie = should end / should end with
kwa nukta = with a period, full stop

So the structure is basically Teacher said every sentence should end with a period.

alisema can be divided as:

a- = he/she
-li- = past tense
-sema = say

So alisema literally means he/she said. Swahili verbs often pack the subject and tense into one word like this.

Swahili often leaves out kwamba when it means that. So both of these are natural:

Mwalimu alisema kila sentensi iishie kwa nukta.
Mwalimu alisema kwamba kila sentensi iishie kwa nukta.

The version without kwamba is very common and sounds normal.

After kila meaning every/each, Swahili normally uses a singular noun. So kila sentensi means every sentence.

If you wanted all sentences, you would use a different structure, such as sentensi zote.

iishie is in the subjunctive, which is commonly used for instructions, requirements, wishes, or reported commands. Here the teacher is not just describing what sentences do; the teacher is giving a rule.

So iishie has the sense of should end or must end, not simply ends.

The i- agrees with sentensi. In Swahili, verbs often show agreement with the subject noun class, and sentensi takes this kind of agreement here.

Because kila makes the idea singular, the verb also stays singular: kila sentensi iishie.

This comes from the difference between kuisha and kuishia.

kuisha = to end, to finish
kuishia = to end at/in/with something

Because the sentence specifies what the sentence should end with, namely kwa nukta, iishie is a very natural choice. It gives the idea should end with a period more clearly.

Here kwa is best understood as with. So kwa nukta means with a period/full stop.

The word kwa has several uses in Swahili, including meanings like by, at, or with, so the exact translation depends on context.

Nukta literally means a dot or point. In writing and punctuation, it means a period or full stop.

So in this sentence, kwa nukta clearly refers to punctuation.

In form, alisema just means said. But because the next verb is in the subjunctive (iishie), the whole sentence feels like reported instruction or a rule.

So the meaning is closer to The teacher said that every sentence should/must end with a period.

No. Mwalimu does not mark male vs. female. It can mean male teacher or female teacher, depending on context.

This is very common in Swahili: nouns like this are usually not grammatically marked for natural gender.

Swahili usually does not use articles like a and the the way English does. So mwalimu can mean a teacher or the teacher, depending on context.

In this sentence, English naturally translates it as the teacher, but Swahili does not need a separate word for that.