Learn Hardcore Swahili: Ukisoma biolojia kila siku, utaanza kuelewa mwili wako vizuri. - If you study biology every day, you will start to understand your body well.

So ukisoma literally means something like if/when you read or if/when you study. It introduces a condition or a repeated situation that makes the second part of the sentence happen.

Is ukisoma more like if you study or when you study?

The -ki- form can mean both if and when, depending on context.

Here, with kila siku (every day), it has a sense of whenever / when(ever) you study biology every day, this result will follow.
In many cases, though, it also works like if: Ukisoma, utafaulu = If you study, you will pass.

So in this sentence, you can understand ukisoma as a mix of if and whenever: a general condition that leads to the result in the second clause.

Why is the second verb utaaanza in the future tense?

The future tense uta-anza → utaanza is used because the result happens after and as a consequence of the condition.

Ukisoma... = If/when you study (regularly)
utaanza kuelewa... = you will begin to understand...

This pattern is very common:

Ukifanya mazoezi, utajisikia vizuri.
If you exercise, you will feel good.

Using the future here highlights that the understanding comes later, as a result of the ongoing habit of studying.

Why do we say utaanza kuelewa and not just utaelewa?

Both are grammatically correct but they are not identical in meaning:

utaelewa mwili wako vizuri = you will understand your body well
utaanza kuelewa mwili wako vizuri = you will start/begin to understand your body well

Utaanza kuelewa uses the verb anza (begin/start) plus the ku- form kuelewa (the infinitive to understand). It emphasizes the process and the idea that understanding will gradually begin, not just suddenly appear.

So the writer wants to stress that studying biology every day will gradually get you started on understanding your body better.

What is the function and position of kila siku in this sentence?

Kila siku means every day. It tells us how often you study biology.

In the sentence, it comes after the object:

Ukisoma biolojia kila siku...
If/when you study biology every day...

You can move kila siku around a bit:

Kila siku ukisoma biolojia, utaanza kuelewa...
Ukisoma kila siku biolojia, utaanza kuelewa... (less common, a bit awkward)

The most natural and common place is where it is in the original: after biolojia.

Why is it mwili wako instead of mwili yako?

This is about noun classes and agreement.

mwili (body) is a class 3 noun (m-/mi- class).
Possessive pronouns must agree with the noun class.

For class 3 singular, your (singular) is wako, not yako.
So:

mwili wako = your (one person’s) body
miili yako = your bodies (plural of body) – now the noun is class 4, which takes yako

Yako is used with noun classes that take a ya- agreement (like class 4, 6, 9, 10).
Wako is used with noun classes that take a wa- agreement (including class 1 – persons – and class 3 – some things like body, tree, etc.).

Do we need to say wewe for you, or is u- in ukisoma enough?

u- in ukisoma already shows that the subject is you (singular), so wewe is not required.

Ukisoma biolojia... = If/when you study biology...
Wewe ukisoma biolojia... = You, if/when you study biology...

You add wewe mainly for emphasis or contrast, like:

Wewe ukisoma biolojia kila siku, utaanza kuelewa mwili wako vizuri; yeye hasomi kabisa.
You, if you study biology every day, you will begin to understand your body well; he doesn’t study at all.

Can vizuri be placed somewhere else in the sentence?

Yes, you have some flexibility, but the most natural position is at the end:

...kuelewa mwili wako vizuri.
...to understand your body well.

Other possible placements:

...kuelewa vizuri mwili wako. – also understandable and acceptable.
Vizuri utaanza kuelewa mwili wako. – changes the focus and sounds less natural here; it can sound more like well, you’ll start to understand your body.

Placing vizuri right after the object (mwili wako vizuri) is smooth and very common for adverbs like vizuri, sana, etc.

Is biolojia a Swahili word or a borrowed word from English?

Biolojia is a loanword, borrowed from European languages (ultimately from Greek via English or other European languages).

It is fully accepted and standard in Swahili:

biolojia = biology
pronounced roughly: bi-o-lo-ji-a

Swahili sometimes has more descriptive alternatives (like elimu ya viumbehai for biology), but in everyday language and in schools, biolojia is the normal word.

Could this sentence use a different tense in the second part, like Ukisoma biolojia kila siku, unaanza kuelewa mwili wako vizuri?

You could say:

Ukisoma biolojia kila siku, unaanza kuelewa mwili wako vizuri.

This would sound more like describing a general pattern that is already happening now:
Whenever you study biology every day, you (typically) start to understand your body well.

However:

Ukisoma..., utaanza kuelewa... is the most natural way to talk about a future result of a habit you are recommending or predicting.

So the original with utaanza fits best if you are giving advice or making a prediction about what will happen if someone adopts that habit.