Pronunciations are not clear
The only thing in DL that really needs improvement is the pronunciations of both words and sentences. I implore you to improve it with good pronunciations of native speakers at least for languages like French and German. You guys are great and many thanks for giving us such a great tool as DL.
The better thing to do to have better pronunciation is to report wrong one. But, seeing many times someone complaining about a wrong french pronunciation when it's perfectly correct (I'm french), I'm afraid that to many non-native french (and no reason to be different for other languages) speaker report correct pronunciation as wrong. And so Duolingo is overflood by false report.
Si I think the best thing to do is to report wrong pronunciation to Duolingo but, every time if one is not native speaker, ask in the "Discuss the Sentence" page to native speaker if it's really not well pronounced.
Some robot's accent, yes with some sentences a little but nothing horrible or terribly bad. And as they will not record each 500 versions [Duolingo's statistic, in average] of each 20.000 sentences [Duolingo's statistic], they have to record each word and after put all this together, so obviously it'll have sometime a little robot's accent, but nothing bad.
And, there is maybe a little robot accent sometimes, but the pronunciation is not wrong (except some cases that we have to report).
NB : I'm only speaking about French.
I'm afraid, except for some -- but not so many -- sentences, that the problem is not the pronunciation of the french lady, but the french pronunciation that's hard for foreigners to get... I say this because I don't find the french pronunciation so bad, so far of my own pronunciation.
The audio is generated by computer automatically. If something sounds wrong report it and (I assume) the Experts will tweak the input text to make the audio sound more natural. The only way to get real voices is to pay someone (which isn't possible on a free site) or ask the community to upload content (which can easily lead to a big mess).
The difference between 'Er' and 'Ihr' in spoken German is driving me nuts, since context is not often helpful. But rather than attribute it to the speaker, I assume that it's just some nuance my ear has yet to pick up on.
I'm from the Southeast US. If I recorded the English lessons, the rest of the world would go stark raving mad. :-D
That's funny. I just started French, and it seems just the opposite to me. For the most part, I find it much easier to understand the German speaker. Perhaps you've become accustomed to hearing 'Duolingo French' and I've become more accustomed to hearing 'Duolingo German', and it's the switch that makes it difficult rather than the language itself.
Concerning your German difficulties: The vowel in 'ihr' is more like the one in 'me' and the vowel in 'er' is more like the one in 'beer'. :)