How I feel learning Russian...
This is exactly my aspect when one of those 'listening' exercises come :) How about you? Are you having as much trouble as me?
я бабушка :D
Native speaker opinion here (based on the sentences I've heard in the placement test): the voice is fine, so if you have difficulties, practise more. The voice is kind of flat and stereotypical and boring (although it is probably best for the students), but it definitely handles pronunciation much better than some of the synth voices I've heard here on Duo.
^This. So, I took Russian last fall and I'm super terrible/rusty with it, but from what I remember, when o is in the syllable that is stressed, it is pronounced like you think an o would be pronounced. When it is preceding the stressed syllable, it is pronounced like the stressed a in Russian is. When it is in any other environment, I think, this is where I might be wrong, it is pronounced as a schwa (the a in about when said at normal speed and not emphasized.) Perfect example of this is the word moloko. It has all three pronunciations of the o in it. I think a is also a schwa sometimes, too.
Then some of the other vowels are pronounced differently depending on if they're stressed or not. I would definitely look around for some pronunciation material to help practice this outside of Duolingo. I forgot how in-depth the tips & notes section goes in on pronunciation and stress, it might be adequate, not sure, but it doesn't hurt to maybe youtube some stuff or pick up a cheap textbook or something maybe. If you know the international phonetic alphabet or do not mind looking up a key for it, check out the wikipedia article on Russian phonology. Definitely worth looking into.
TL;DR Most of the Russian vowels, if not all, change pronunciation based on if they're stressed or not.
I think it's a practice thing. As a non native, formerly fluent speaker, the voice isn't perfect, but most of the listening exercises it throws at me feel like freebies, with a few now and then that take a lot of repeats/listening slow. I honestly think it's a practice thing. New language, new alphabet, give yourself a break for not being fluent right off the bat, you'll get there!
Yes, a coupe of words I had to check on forvo. Definitely a difference in clarity. One I reported because there was enough of a difference. Another glitch I reported was in one sentence the bot was sounding the same words twice at the same time. Like if two people were saying the same word at the same time. It created an almost echo-like effect.
I started learning Russian with Pimsleur, which is basically all audio, so listening is probably my best skill and I don't have too much of a problem with the listening exercises here. The hardest thing for me is writing in Cyrillic, followed closely by reading in Cyrillic.
I think its really great that the course is released! Thanks a lot to the team behind it! However, some parts of the listening is HARD :) Also I find the course a bit too strict on nailing the spelling really to the letter. I wonder if the course could become more relaxed on the spelling check and allow more of the "almost correct" type of check? My personal focus is primarily on listening+speaking, so I consider going for Pimsleur first, and then after that perhaps return for another round of spelling torture here at Duolingo :) ... и ы й ий ии е etc ... sound all so similar! :s short sentences are not a problem to write correctly.. but the long sentences really are hard to nail ... (plurals, definite forms, indefinite etc) phew!! :)
If your focus is on listening and speaking, I indeed definitely advise you to begin with Pimsleur and return to Duolingo when you feel you begin to understand how Russian sound (because with Pimsleur alone you won't learn a lot of vocabulary and grammar before a long time).
A problem with Pimsleur is that at the beginning, you learn only very formal way of speaking (Вы, …) and must wait the second level (so after about 30 lessons) to begin using more informal sentences (Ты, …).
I would say that if I hadn't taken private russian lessons prior to this I would be struggling pretty mightily in those first few lessons. It's perfect for me - I know the grammar of the first section well, but my spelling is abysmal, and I can see it will really help me with that. Darned soft signs! Darn them!