Baada ya kukimbia, ninahitaji maji kidogo.

Baada ya means after.

In Swahili, baada usually takes ya before the thing or action that follows it:

• baada ya kazi = after work
• baada ya chakula = after food / after the meal
• baada ya kukimbia = after running

So ya is not optional here in normal usage; it is part of the common pattern baada ya + noun/verb-noun.

Because after baada ya, Swahili normally uses the infinitive form of the verb.

• kukimbia = to run / running

Here, the infinitive works a lot like an English -ing form after a preposition:

• baada ya kukimbia = after running

If you said baada ya nakimbia, that would be ungrammatical. Nakimbia means I am running / I run, but after baada ya you want the action as an idea or event, not a fully conjugated clause.

Ninahitaji can be broken down like this:

• ni- = I
• -na- = present tense
• -hitaji = need

So:

• ni-na-hitaji = I need / I am needing

Swahili often combines the subject marker and tense marker directly onto the verb, so one word can express what English needs several words for.

Because the ni- at the beginning of ninahitaji already means I.

So:

• ninahitaji = I need

You can add mimi for emphasis, but you usually do not need it:

• Mimi ninahitaji maji kidogo. = I need a little water.
  (This sounds more emphatic, like I need water.)

In ordinary speech, ninahitaji by itself is enough.

Maji means water, and in Swahili it is treated as a noun that normally appears in this form only.

So even though English distinguishes:

• water (uncountable)

Swahili simply uses:

• maji = water

You do not need an article like a or the unless the context adds that meaning. Swahili generally does not use articles the way English does.

So:

• ninahitaji maji = I need water

In Swahili, modifiers often come after the noun they describe.

So:

• maji kidogo = a little water

Here kidogo means a little, a small amount, or some in this context.

That is why the order is not like English little water, but rather water little from an English learner’s perspective.

It means a little water.

In this sentence, kidogo refers to amount, not physical size. So the idea is:

• ninahitaji maji kidogo = I need a little water / I need some water

That is a very natural interpretation here.

Yes, to some extent.

The original sentence:

• Baada ya kukimbia, ninahitaji maji kidogo.

is very natural and puts the time/context first: After running...

You could also say:

• Ninahitaji maji kidogo baada ya kukimbia.

This also makes sense and means the same basic thing. The difference is mainly one of focus and flow:

• Baada ya kukimbia, ... = sets the scene first
• Ninahitaji ..., baada ya kukimbia = starts with the main statement

The comma is helpful in writing because Baada ya kukimbia is an introductory phrase.

So this is good:

• Baada ya kukimbia, ninahitaji maji kidogo.

But in informal writing, people may leave it out:

• Baada ya kukimbia ninahitaji maji kidogo.

Both are understandable. The comma mainly makes the sentence easier to read.

A simple pronunciation guide is:

• Baada ya kukimbia, ninahitaji maji kidogo.
• bah-AH-dah yah koo-keem-BEE-ah, nee-nah-hee-TAH-jee MAH-jee kee-DOH-goh

A few useful points:

• Swahili vowels are usually pronounced clearly and consistently:
  • a = ah
  • e = eh
  • i = ee
  • o = oh
  • u = oo
• Stress is usually on the second-to-last syllable:
  • ku-kim-BI-a
  • ni-na-hi-TA-ji
  • ki-DO-go

Yes. In many cases, baada ya + infinitive can be translated naturally in English in more than one way:

• after running
• after I run
• after I have run

The exact English wording depends on context. Swahili does not force the same distinction here that English sometimes does, so baada ya kukimbia is a flexible and very normal expression.