Is the Russian voice very accurate?
It is very hard to distinguish certain letters/parts of words. O vs и vs e is tough. Sometimes the в is impossible to here, sometimes р and с and з sound similar. Vowels in general can be a lot of guesswork or basically trying to remember how it was spelled. Is this just how Russian is or is the voice making it even harder than a real person would sounding these words out to beginners?
Love the course
It is pretty accurate. There are, of course, some glitches (which were reported by me, at least, and I guess other Russian speakers as well), but overall it is not bad. Nevertheless, there were some sentences which were not trivial even for a native speaker's ear. For instance, I think the name Anna was chosen poorly, due to its similarity to "Она" (she).
I too find the vowel endings difficult to tell apart, but I think that's just how Russian is (Russian-speakers will just automatically listen for things like that, along with little words like в and с wedged between other words). I never thought the TTS's р is unclear (in the Turkish course, it's always sounding like 'sh'; in Russian, it actually sounds like an 'r'), but its л, at the beginning of a sentence, often sounds strange to me.
I'm sure the TTS isn't perfect, but without being qualified to criticise it, I just read the comments pages and assume it's a reasonable approximation unless I see otherwise (or unless there is really obvious mangling going on).
I actually really like the Russian voice in the recordings. It sounds exactly like Russian people sound when I speak to them. It is hard to tell some of those sounds when you listen to native Russian speakers. I find they don't always pronounce the endings that clearly. The 'o' sounds like a weak 'a' if it isn't stressed. And the words that end in 'e' with prepositions often sound like и to me. The в and K run into the next word when they mean 'in', 'towards', etc. I think English does a lot of linking of words too.
The 'o' is supposed to sound like a weak 'a' when unstressed. But even I, a Russian speaker, failed a few times catching that extra "и" between words, when the first ends with "и" (пироги и конфеты - cakes and candies). While my example is somewhat artificial, and a native speaker would sense there must be an "and" between the words, I did meet some real sentences where it was unclear.
The voice has a lot of glitches, and I do not like the intonation (sounds off not only in questions, but in some declarative sentences, too). However, if you mix up some sounds, the most likely reason is that you are not used to the language yet.
Telling different sounds apart is only half of it: neither Russian, nor English are spelt phonetically, so you cannot guess the spelling of a word solely by how it sounds. In Russian, however, you might produce a good guess.