Hi, I was learning the Plurals lesson. It says that masculine nouns would have -er ending. But the Plural for Bear (Bar) is Die Baren. Shouldn't it be 'Die Barer' ?
Sorry, but that what Duolingo says about the -er ending of masculine nouns is not right. There are a lot of masculine nouns without -er ending, e.g. der Vogel - die Vögel; der Arm - die Arme; der Hund - die Hunde and so on. You can find some hints how to form plurals of german nouns here> http://mein-deutschbuch.de/pluralbildung.html. I recommend to learn the nouns in singular and plural together with the appropiate article. It is hard but effective. Good luck for further studying.
Unfortunately, there are more than one rule plus a lot of exeptions. Maybe you give a second look at this page: https://deutsch.lingolia.com/de/grammatik/nomen/plural
Regarding a vs. ä (= ae) etc. It is very important that you learn the right letter. Otherwise there could be a lot of misunderstandings in the future.