PERCE_NEIGE ,sorry I couldn't reply directly to your comment. I guess the system doesn't allow replies past level 8 of replies.
I will not give a figure regarding the number of classes because I didn't research on that. However I can comfortably say that one of the Bantu languages I know has as many as 20 classes! Don't freak out since most are in pairs of singular / plural.
As for your last question, it depends on which other Bantu language you speak. Some are mutually intelligible while others are completely mutually unintelligible. It helps to know another Bantu language since language concepts will be similar.
Hope that answers your questions
I want to say no Niger-Congo language has all 20+ classes, but it's easier for linguists to make an all-inclusive list for the whole family, and then figure out which of those classes each individual language has.
Going by the notes from my "presearch" (looking for materials before the course was relaesed) gave a figure of 15 noun classes for Kiswahili: 1-11, 14, and 16-18.
I'd assume it would be like a lot of other linguistic families: those in close proximity are probably closely related and more likely to be more mutually intelligible, while those with less contact will have less in common. I suspect that learning one Bantu language can give you insight into how other languages in the family are structured, and might help you be better prepared (versus, say, trying to learn Igbo from scratch), but I doubt that learning Kiswahili would automatically let you understand another Bantu language without studying it.
AustinLack means that "you" in English can be translated by singular, and plural.
If you translate English to French, for instance, you'll have you -> tu (singular) and you ->(plural).
The "you all" is not mandatory, you can use it to avoid the confusion between you plural and you singular if you are an English speaker.
Sure, but ninyi can also be used to address two people and, apart from certain US dialects, "you all" cannot and would have to be "you both".
In my dialect, for plural "you" we say "you guys" but that's informal and potentially regarded as exclusively masculine (although it is not used as such) or even more informal "yous", "you lot" or "you mob".
There really is no perfect English equivalent to a second person plural pronoun which is appropriate in all situations or all dialects of English and simply using "you" for both singular and plural is the formal standard across the English speaking world.
Some grammar books use "thou" for singular and "you" or "ye" for plural, but having that in a duolingo course would get ridiculous pretty quickly especially seeing as these are pretty unfamiliar to most native English speakers and will confuse most .
unakula = thou eatest
mnakula = ye eat
Jina lako ni nani? = What is thy name?
Unanipenda. Ninakupenda = Thou lovest me. I love thee.
Duolingo tries to be clear and precise with their translations where it is useful, as it would be here, but they don't like to get into unidiomatic translations or things that are restricted to only one dialect.
I don't think so. Many languages make the distinction between plural polite you, singular polite you, "normal" plural you, and singular you. See latin languages for instance (except French)
As an English speaker, your confusion is from English doesn't make the difference between plural and singular you, and has dropped its polite form (or more exactly dropped the normal form to use the polite form as the normal one)
It's sometimes hard to hear the difference in speech but there is a difference when written. "Americans" the noun is translated as "Wamarekani" whereas the adjective is actually two words, so "American people" would be "watu wa Marekani" (people of America). Then for singular it would be "Mmarekani" (an American) or "mtu wa Marekani" (person of America).
You're right. the singular of "wamarekani" is "mmarekani." you just linger a bit on the "m" at the front to differentiate it from "Marekani" (the country). Definitely don't do "mamarekani". As far as I know it's just nonsense but it would imply it's in the ji/ma noun class rather than the m/wa class. A lot of foreigners make that mistake though. It's hard to understand that a consonant by itself can be a syllable, but embrace the humming sound of that "m" and don't let yourself be tempted to throw an unnecessary "uh" in there. "muh-marekani" is tempting, but sounds terrible!