translation issue: ninyi (is rendered you, but could also be you all)
Therefore: They are Africans and You all are Americans - should be an acceptable translation.
They fixed it
Is the a pronounced double length in this case?
Yes, the A is longer, but not exaggerated . So it would sound like waah-frica, not Wah - ah- frica
How do I know when to capitalize words? Is it like German?
does Wamarekani refer to Unitedstatesians specifically or to inhabitants of the Americas in general?
It is supposed to be "nyinyi"
Would "they are African and we are American" work? If not, what are the adjectives to describe African and American people?
*you are American, but yes, that is another translation; Swahili doesn't have a nationality adjective distinct from the noun