What is the difference between "kwa" and "la"?
(The hint gives "kwa" as translation for "for")
la is basically "of", so it's basically "juice pineapple"
I'm not positive, but I think "kwa" is always adverbial, meaning "with", "at", "to" etc, relating to the whole sentence, whereas the other -a words always refer back to the previous noun.
Finally, I can't hold myself back anymore with this word juisi. It must be a Kenyan thing. In Tanzania the translation for (fruit) juice is: Maji ya matunda.
My Kenyan fiancee says maji ya matunda too. She thought juisi was a Tanzanian thing...