Having read through the entire list of posts it's amazing how many people claim 'little' by itself is wrong - most often because they have never heard it used that way. Sad - the world would be a terrible and inconceivable place if a thing were ruled out simply because a person had never heard of it before. If this Spanish Duolingo class teaches you something about English - then embrace it!
I'm not a native English speaker, so it was a bit of a puzzle for me, but I managed to get it correct at my first try and learned something new in English. I love it!
That’s nothing you should hear them talk about the word “much” by itself.
I am brazillian and I found so interesting that the native English speakers didn't know about "little". Little is little you can for example work little. Little isn't not much. Little is little.
Yes, “little” comes with a judgmental attitude that it is not enough, but “not much” often does also.
Languages are constantly evolving, look at 15th century english compared to current day english. Just because what is technically correct doesnt mean people actually say it that way. I for one want to learn how language is currently used not what is technically correct.
I feel it has more to do with pragmatics than you're considering. Frankly, using "little" on its own is vague and leaves the text up to interpretation. That's simply bad form for a modern language, and so language evolves.