Which Arabic dialect do you speak? In Egyptian Arabic, "engeltera" is stressed penultimately, but that goes with the rules of the dialect, so I'm wondering if other dialects really pronounce it "2ingiltiraa," with antepenultimate stress. Won't lie, sounds weird to me, but it would make sense, since the "gil" is the heavy syllable here.
The Egyptian and Yemeni dialects pronounce it as /g/, and it does originally come from Proto-Semitic /g/, so there is definitely a connection between ج and /g/. This particular case is a bit complex though, because as a European loanword, even non-Egyptians/Yemenis pronounce it with a /g/ sound, but I'm not sure how everybody spells it. Normally, Egyptians spell the /g/ sound using ج, the Gulf region spells it using ق, the Levant using غ, Tunisia using ڨ, and Morocco using ڭ. But in this case, the word has kind of been Arabized and standardized, so I'm not sure whether it receives the loan-word treatment or whether everybody spells it the same way. I do know the word "ingliizi" ("English") can be spelled with both a ج and a ك, but I don't recall ever seeing ingiltiraa spelt with a ك. Or have I? I will tell you that another word you encounter frequently in this course, كراج ("garage"), can be spelt in all sorts of ways, and the Egyptian way is: جراچ. Sorry I can't be of more help. :(
Best thing to do is report it as a bug to Duolingo here: https://support.duolingo.com/hc/en-us/requests/new
I've reported it as well so I hope they will be able to fix this soon. :-)
I'm not completely sure, but و is pronounced after a noun when it's in definite form (usually with ال before the word, e.g. the house etc) and ون (a house) when indefinite. Names are seen as indefinite. From what I've read this is the "correct" way of speaking, but usually when speaking it can be dropped
Mmm.. Jimmie, this all goes down to the rules and definitions of Arabic grammar. I wouldn't want to complicate things for you here just yet, but, simply put, even native speakers - when at school- don't learn grammar (including complex word ending sounds or forms) for the first few years at school.