So here, Duolingo adds the sound "u" before the ه in اِسْمها ; but in the last exercise, the added vowel was "i", in بيتها. Is there any logic, or, at least, rules? Or is it 'au choix'?
Nominative case. ismu (name) + há suffix (her) = her name.
Thank you, TJ_Q8. That's very interesting. So those who say (and it's on Youtube!) that you can choose which short vowel you want to use for euphony before the ه are talking nonsense?
My guess is that these people were teaching a dialect, or making it easy for learners by neglecting the grammatical details and just teaching the essential words in standard Arabic.
OK. Makes sense.