Duolingo didn't write about it but I read that animals ( which should follow grammaticaly M-WA class ) in plural forms follow the class which they belonge to. It would explane - simba mwili. :)
Since "we" indicates at least two persons, does this sentence mean one ear each person or one person with two ears and the other with none?
The forms used in counting are essentially the N-class forms. The N- before a W becomes mb-. The actual root of "two" is "-wili".
Watu wawili two people
Miti miwili two trees
Maembe mawili two mangoes
Vitu viwili two things
Simba wawili two lions (animate!)
Nyuso mbili two faces
Simba mbili? Although it's N/N, doesn't simba follow M/Wa grammar rules because it is animate?
Oh yes, oops, sorry! I'll edit it to not mislead anyone who comes later.
(The N class animate nouns seem to use the N class possessives though, ya, za, yangu etc. and my theory is that it's because the nouns don't show number and the M-WA possessive forms don't either (all starting with w) so it's like a way of maximising the chance that you'll know if it's singular or plural.)
yes, any animate (living beings) are using the concordancce of m-/wa-; pretty much only case in which "things fall out of their class"