Hearing plurals in French
How do you hear plurals in French in simple sentences (without adjectives, verb changes, etc.)?
For example, I always fail to hear the difference when Duolingo asks me to transcribe either of these sentences:
Nous lisons les livres. OR Nous lisons le livre.
I have listened to several other sources, and still cannot hear a difference. Am I missing something subtle?
In the sentence you gave as an example "livre" & "livres" is pronounced exactly the same. In this case the key would be to distinguish between "le" & "les" which sound different. Leuh/lay. You can find example audio for these words anywhere including quick trip to google translate. They do not sound really alike at all once you grow used to hearing them. Luckily in a lot of cases you don't really need to hear the difference yet because many sentences have other indicators like various pronouns and verb conjugations and adjective pluralizations. Anyway if you were talking to someone and they told you "Nous lisons le livre" and you didn't hear whether it was a "le" or a "les" you probably wouldn't sweat it because you would know whether they were talking about a single book or a series. Otherwise they wouldn't have been using the article in the first place. Don't get discouraged! Remember that with duolingo you are learning sentences without context, and context is a beautiful thing.
You need to be able to hear the difference between le/la and les. There is definitely a difference. If there is a vowel at the beginning of the vowel, you should hear an s sound before it if it's a plural, since the s at the end of les would be pronounced. Besides that, it's just a matter of context, which does rely on verbs/adjectives/etc.
If a particular lesson is giving you trouble, you can temporarily turn off audio exercises just to get past it. Though you should be sure to learn the material.
Based on my own experience as a native English speaker, French has vowel sounds that are initially indistinguishable from each other. With time and practice your ears will get trained and you will be able to hear the differences.
The letter "e" in particular can be a tricky one because in addition to sometimes being silent it is pronounced in at least three different rule based ways. The "e" in the word "le" is pronounced a bit like the "uh" sound in the word "Tina'. The word "les" is pronounced a bit like "lay" without rounding your lips to say the "y" at the end. Neither of these examples are exact pronunciations, but they are fairly reasonable approximations.
I agree with DovahFerret that the articles le/la and les give the cue. Also du, des. I'm a beginner at French but I was able to pick up on these after a few lessons. I usually close my eyes at the beginning of a translation question to try and see if I can figure out the sentence without reading it.