Maji yanaanza kuchemka, tia majani ya chai.

Because maji belongs to noun class 6 in Swahili. This class takes the subject prefix ya-, so you get maji yanaanza.

This can feel strange to an English speaker because water feels singular in English, but in Swahili maji is treated grammatically as a class 6 noun. So the verb has to agree with maji, not with the English idea of singular water.

Yanaanza can be broken down like this:

• ya- = subject prefix for noun class 6
• -na- = present tense
• -anza = begin, start

So yanaanza literally means it/they are beginning, with the exact English wording depending on the noun. With maji, it means the water is starting.

After -anza (to begin/start), Swahili normally uses the infinitive form of the next verb, and infinitives usually begin with ku-.

So:

• kuchemka = to boil
• yanaanza kuchemka = is starting to boil

This is very similar to English start to boil.

This is an important difference:

• kuchemka = to boil / be boiling
  
  • intransitive: the thing itself is boiling
• kuchemsha = to boil something
  
  • transitive: someone causes something else to boil

In this sentence, the water itself is beginning to boil, so kuchemka is the correct choice.

Compare:

• Maji yanachemka = The water is boiling
• Ninachemsha maji = I am boiling water

Tia means put or add.

In cooking instructions, tia is very common for adding ingredients to something. So here it means add the tea leaves.

Depending on context, Swahili recipes may also use verbs like weka (put/place) or ongeza (add/increase), but tia is perfectly natural.

Because tia is an imperative form: a command directed at one person.

In Swahili, a simple positive singular command usually appears without a subject pronoun. So:

• tia = add! / put!

You do not need a separate word for you.

If you were speaking to more than one person, the plural imperative would be:

• tieni = add! (to multiple people)

Because majani is the plural form:

• jani = leaf
• majani = leaves

Since tea is made with multiple leaves, majani ya chai = tea leaves is the natural expression.

Also, majani belongs to the same noun class family as maji, which is why you also see agreement forms like ya with it.

Literally, it means leaves of tea.

Here:

• majani = leaves
• ya = a connector meaning of, agreeing with majani
• chai = tea

So majani ya chai is the normal Swahili way to say tea leaves.

The -a connector changes form to match the noun class of the thing being described. Since majani is class 6, the connector appears as ya.

Because Swahili does not usually use articles like a, an, or the.

So:

• maji can mean water or the water
• majani ya chai can mean tea leaves or the tea leaves

The exact meaning depends on context. In a cooking instruction, English naturally uses the, but Swahili usually does not need a separate word for it.

Yes, that is the idea.

The sentence gives two actions in sequence:

1. Maji yanaanza kuchemka
2. tia majani ya chai

In English, we might naturally say When the water starts to boil, add the tea leaves. In Swahili, this kind of recipe-style instruction can be written simply with a comma, and the timing is understood from context.

A more explicitly when/once style version could be:

• Maji yakianza kuchemka, tia majani ya chai.

But the original sentence is normal and natural.

Yes.

• yanaanza kuchemka = is starting to boil
• yanachemka = is boiling

So yanaanza kuchemka suggests the boiling is just beginning, while yanachemka means the water is already boiling.

Yes, in normal everyday Swahili, maji is treated as a noun of class 6 and takes class 6 agreement.

So you will commonly see things like:

• maji yamechemka = the water has boiled
• maji yanatosha = the water is enough
• maji yameisha = the water is finished / used up

This is a good example of how Swahili grammar follows noun classes, not English ideas like singular, plural, or uncountable.