Learn Hardcore Swahili: Ninapoandika barua, ninapenda kukaa katika sebule. - When I am writing a letter, I like to sit in the living room.

ninapoandika:
- focuses more on time: at the time that I write / whenever I write
- is a relative tense form with -po-
- often sounds a bit more formal or written style.
nikiandika:
- uses the -ki- form, often meaning when / if / whenever / while
- can suggest a condition as well as time: if/when I write
- feels a bit more informal and very common in speech.

In many everyday sentences, both could work, but ninapoandika is a very clear “when (I am) writing” in a time sense.

Why do both verbs start with ni-: ninapoandika and ninapenda? Can I drop one ni- like in English?

In Swahili, every finite verb must have its own subject prefix, even if the subject is the same in the whole sentence.

ninapoandika = ni- (I) + -na- (present) + -po- (when) + andika (write)
ninapenda = ni- (I) + -na- (present) + penda (like)

You cannot normally say *Ninapoandika barua, napenda kukaa… and omit the ni- in the second verb; that would be ungrammatical.

So unlike English (where we can say “When I write letters, like to sit…” and understand the missing I), Swahili must repeat the subject marker on each verb:
Ninapoandika barua, ninapenda kukaa…

Why is it ninapenda kukaa and not ninapenda kaa?

After many verbs (like penda = like, want, begin, try, etc.), the next verb is put in the infinitive form with ku-:

kukaa = to sit / to stay
kaa = bare verb root, which cannot stand by itself here.

So:

ninapenda kukaa = I like to sit / I like sitting
*ninapenda kaa is wrong.

The pattern is very common:

ninataka kula = I want to eat
nimeanza kusoma = I have started reading
anapenda kuogelea = he/she likes to swim

What does barua mean here? Why isn’t there a or the like in English?

Swahili does not have articles (a, an, the). The noun barua simply means letter. Whether it is a letter or the letter is understood from context.

So:

Ninapoandika barua can mean:
- When I write a letter (any letter, in general), or
- When I write the letter (a specific letter already known from context).

There is no change in the Swahili form; everything depends on the situation and context.

What is the function of katika in katika sebule? Could I say the sentence without it?

Katika is a preposition meaning roughly in / inside / within.

katika sebule = in the living room

You have a few options:

Ninapoandika barua, ninapenda kukaa katika sebule.
- perfectly correct; fairly neutral/standard style.
Ninapoandika barua, ninapenda kukaa sebuleni.
- here sebuleni is the locative form of sebule, also meaning in the living room.
- This is very natural and common.
Ninapoandika barua, ninapenda kukaa sebule.
- without katika or the -ni locative ending, this can sound a bit incomplete or less natural.
- For places, you normally use either a preposition like katika or a locative ending like -ni.

So katika sebule and sebuleni are both good ways to say in the living room.

What is the difference between sebule and sebuleni?

sebule = the noun living room / sitting room (basic form)
sebuleni = locative form, meaning in the living room / at the living room

In many place nouns, adding -ni gives a location meaning:

nyumba = house → nyumbani = at home
shule = school → shuleni = at school
sebule = living room → sebuleni = in the living room

So:

katika sebule ≈ sebuleni = in the living room

Could I move the when-clause to the end: Ninapenda kukaa katika sebule ninapoandika barua?

Yes. Swahili word order is quite flexible with subordinate clauses. Both are correct:

Ninapoandika barua, ninapenda kukaa katika sebule.
Ninapenda kukaa katika sebule ninapoandika barua.

The meaning is the same. The difference is just what you put first for emphasis or flow:

Version 1 starts with the time setting: When I write a letter…
Version 2 starts with the preference: I like to sit in the living room when…

What is the nuance of kukaa here? Does it mean “sit” or “stay” or “live”?

The verb kaa is quite broad. Depending on context, kukaa can mean:

to sit / be seated
to stay / remain
to live (somewhere) / reside

In this sentence:

ninapenda kukaa katika sebule ≈ I like to sit in the living room
(or I like to be in / stay in the living room)

If you wanted to emphasize “to sit down / to be seated” more specifically, you could also see or use kuketi, but kukaa is extremely common and completely natural here.

Is ninapenda like English “I like” or “I am liking”? What tense/aspect is it?

Ninapenda is formed with:

ni- = I
-na- = present tense
penda = like / love

It usually corresponds to simple present I like (or I love), not I am liking.

The -na- present tense in Swahili often covers:

current ongoing actions:
- Ninasoma. = I am reading.
general habits / states:
- Ninapenda kahawa. = I like coffee.

So Ninapoandika barua, ninapenda kukaa katika sebule naturally means When I write a letter, I like to sit in the living room, not “I am liking”.

Why doesn’t the verb andika show agreement with barua?

In Ninapoandika barua:

ni- = I (subject)
andika = write
barua = letter (object)

The verb agrees in person/number with the subject, not with the object. The subject here is I, so the agreement prefix is ni-.

Swahili has object markers, but they are:

optional, and
usually used when the object is definite/specific or already known.

You could say:

Ninapoandika barua, ninapenda kukaa katika sebule. (natural and normal)
With an added object marker it might become something like Ninapoziandika barua…, but that suggests specific, already-known letters and is less necessary here.

So andika doesn’t change for barua; it’s correctly agreeing with I, not with the object.