Mtoto alitikisa chupa ya juisi kabla ya kuimimina kwenye glasi.

It breaks down as a-li-tikis-a:

• a- = the subject marker for he/she with a class 1 noun like mtoto
• -li- = past tense
• tikis- = the verb root meaning shake
• -a = the final vowel

So alitikisa means he/she shook.

Mtoto just means child. It does not tell you the gender.

So this sentence could mean:

• The boy shook the bottle...
• The girl shook the bottle...
• The child shook the bottle...

You need context if you want to know whether the child is male or female.

Ya is the connector meaning something like of here.

So:

• chupa = bottle
• juisi = juice
• chupa ya juisi = bottle of juice

The important thing is that this connector agrees with chupa, the head noun. Since chupa is a class 9 noun, the connector is ya.

If it were plural, you would usually get za instead:

• chupa za juisi = bottles of juice

In this sentence, it most naturally means a/the bottle of juice.

Swahili often uses this noun + ya + noun structure where English might use either:

• bottle of juice
• juice bottle

But here, because the bottle contains juice and the next action is pouring, bottle of juice is the most natural interpretation.

Kabla ya means before.

It is a very common expression. It can be followed by:

• a noun
  
  • kabla ya chakula = before food / before the meal
• an infinitive
  
  • kabla ya kuondoka = before leaving

Here it is followed by kuimimina, so the whole phrase means before pouring it.

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

So:

• mimina = pour
• kumimina = to pour

After kabla ya, Swahili normally uses this infinitive form. That is why you get kabla ya kuimimina = before pouring it.

Because -i- is an object marker meaning it.

So kuimimina breaks down like this:

• ku- = to
• -i- = it
• mimin- = pour
• -a = final vowel

So kuimimina means to pour it.

If you said kumimina with no object marker, it would mean just to pour, without saying what is being poured.

In context, it most likely refers to juisi — the juice.

So the meaning is:

• before pouring it into the glass
  = before pouring the juice into the glass

Grammatically, though, there is a small ambiguity: chupa and juisi are both class 9 nouns, so the same object marker -i- could match either one. Context makes it clear that the child is pouring the juice, not the bottle.

If you wanted to make it totally explicit, you could say:

• kabla ya kumimina juisi kwenye glasi

Here it is best understood as into the glass.

Kwenye is a locative word that can often be translated as:

• in
• on
• at
• sometimes into, depending on the verb and context

Because the verb is pour, English naturally says into the glass. So even though the Swahili wording is locative, the movement idea comes from the action of pouring.

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

So:

• mtoto can mean a child or the child
• chupa can mean a bottle or the bottle
• glasi can mean a glass or the glass

Context tells you which one is meant.

Yes, quite similar.

The basic order is:

• Mtoto = subject
• alitikisa = verb
• chupa ya juisi = object
• kabla ya kuimimina kwenye glasi = time/sequence phrase

So it follows a pattern close to English:

• The child shook the bottle of juice before pouring it into the glass.

That said, Swahili is helped a lot by agreement markers, so it can sometimes be more flexible than English.

Yes. That is a perfectly natural way to say it, and it is even less ambiguous.

Compare:

• kabla ya kuimimina kwenye glasi = before pouring it into the glass
• kabla ya kumimina juisi kwenye glasi = before pouring juice into the glass

The first version uses an object marker (it). The second repeats the noun juisi. Both are possible; the second is clearer if you want to avoid any doubt about what is being poured.