Mwalimu wa usafi anasema ni muhimu kuosha mikono kabla ya kula.

Literally, mwalimu wa usafi means teacher of cleanliness/hygiene.

The word wa is a connector meaning of in this kind of phrase. It links two nouns:

• mwalimu = teacher
• usafi = cleanliness, hygiene

So:

• mwalimu wa usafi = teacher of hygiene / hygiene teacher

This -a connector changes form to match the noun class of the first noun. Since mwalimu belongs to the m-/wa- class, the connector appears as wa.

Anasema can be broken down like this:

• a- = he/she
• -na- = present tense marker
• -sema = say, speak

So anasema means he/she says or he/she is saying.

In this sentence, it is most naturally understood as says.

Ni is the copula, similar to is/are in English in many simple statements.

So:

• ni muhimu = it is important / is important

In Swahili, this structure is often used impersonally. There is no separate word for it here. The idea is simply:

• ni muhimu kuosha mikono = it is important to wash hands

So even though English needs it, Swahili does not.

The prefix ku- is the infinitive marker, like to in English verbs.

So:

• kuosha = to wash
• kula = to eat

In this sentence:

• kuosha mikono = to wash hands
• kabla ya kula = before eating / before to eat

Even though English sometimes uses -ing after before, Swahili often keeps the infinitive with ku-.

Kabla ya is the normal expression for before when it is followed by a noun or infinitive phrase.

So:

• kabla ya kula = before eating
• literally: before of eating

The ya here is part of the fixed pattern kabla ya .... You should learn it as a chunk:

• kabla ya kazi = before work
• kabla ya kwenda = before going
• kabla ya kula = before eating

Mikono is the plural of mkono:

• mkono = hand, arm
• mikono = hands, arms

In this sentence, mikono means hands, because people normally wash both hands before eating.

This noun belongs to the m-/mi- noun class:

• singular: m-
• plural: mi-

So:

• mkono
• mikono

It can mean both, depending on context.

• usafi = cleanliness
• in practical contexts, it can also mean hygiene

So mwalimu wa usafi could be understood as:

• teacher of cleanliness
• hygiene teacher
• possibly health/hygiene teacher, depending on the situation

A learner should know that many Swahili nouns have a meaning range that depends on context, not just one exact English equivalent.

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

So:

• mwalimu can mean a teacher or the teacher
• mikono can mean hands or the hands, depending on context

The listener understands the intended meaning from the situation, not from a separate article word.

That is why Mwalimu wa usafi anasema... can naturally be translated as The hygiene teacher says... even though there is no separate word for the.

This is a very common Swahili pattern:

• ni muhimu = it is important
• kuosha mikono = to wash hands

So the structure is:

• ni + adjective + infinitive phrase

Examples:

• ni rahisi kusoma = it is easy to study/read
• ni vigumu kuelewa = it is difficult to understand
• ni muhimu kuosha mikono = it is important to wash hands

For an English speaker, it helps to think of this as an impersonal expression: it is important to...

Yes. The tense marker -na- often covers both simple present and present progressive, depending on context.

So anasema can mean:

• he/she says
• he/she is saying

In this sentence, says is the most natural translation, because it sounds like a general statement or advice.

Yes, it is very common and natural.

• kuosha = to wash
• mikono = hands
• kuosha mikono = to wash hands

This is the normal way to say wash your hands / washing hands, depending on context.

If you want to be more specific, Swahili can also express possession, for example:

• kuosha mikono yako = to wash your hands

But in general statements like this one, kuosha mikono is perfectly natural.