"My daughter is very cute."
Is the lexical material in duolingo somehow representative of Chinese mainstream culture? I mean was the material intentionally picked in order to provide an insight into the Chinese culture, or is it simply that the social mindset of people working in the Chinese section leaked into the product?
Well, there is actually a lot of thing hidden underneath. I'll try to explain it in a more grammatical way.
In Chinese (and many other east Asian languages like Japanese and Korean), you can use a "adjective-like thing" as a predicate. You may have already learned earlier that 我很可爱 is valid Chinese although you don't see the verb "be" (很 is not be!).
Here I say "adjective-like thing" because 可爱 itself is not yet an adjective. It's hard to describe it using conceptions from English grammar.
的 is the attribute marker. 可爱的 is a true adjective. 地 is the adverbial marker. 可爱地 is a true adverb.
And in this case, the adjective 可爱的 cannot used as predicate anymore. It requires a verb:
Now it's grammatically correct, although a bit weird.
And in real life, you can omit the verb "be" to express intimacy (try to imagine it in English):
Because they are trying to teach us something new, namely, 非常, like xnaut said, 非常 is stronger than 很. There is more to this of course, but, this is good enough explanation for now. There are websites, youtube, etc that can give you more info, such as: https://chinese.yabla.com/chinese-english-pinyin-dictionary.php?define=%E9%9D%9E%E5%B8%B8. We have different ways of saying the same thing in English and we use different words depending on what we want to convey and emphasize, well, so does Chinese.