Unusual / surreal sentences
Everybody has noticed some surreal sentences, which clearly no one would ever think of uttering. I have no problem with those. Most of them are so unusual anybody can see no one would say them, in any language, e.g. "Your flies are in my plate".
However, this raises an issue in my opinion. There are instances, albeit less usual, when I question myself if what I'm reading could really be said by a native, or if it's just one more contrived sentence by Duolingo, e.g. "La sua tigre è dolce." / "His tiger is sweet". In this case, I was unsure if in Italian one can really say "sweet" to describe a character, be it human or animal.
Again, I'm not nitpicking and I'm not concerned with the likeliness of an event (a person breeding flies in the kitchen, or a child drinking oil, or whatever), but with appropriate word usage.
I has occurred to me the reason of this might be the way Duolingo comes up with sentences. If they're not entirely generated by humans, that would explain it. If that's not the case, please consider this, Duolingo staff.
Yeah, I've heard that argument. Personally, I don't find them effective at all. For me, that's what I would call "cognitive noise". Mnemonics are great, provided they make some sense. Anyway, that's a moot point, if they're compromising proper language usage, even if just in some cases.
I understand your point there are lots of sentences in the Spanish version which are either very uncommon phrases or just not possible in the real world. I question the usefulness of phrases like these in learning a language. Perhaps they are beneficial in learning sentence structure and so on but perhaps they are not as good as learning how people actually speak. I remember all my school french books had loads of dumb sentences in that people would never say. Perhaps a language expert would want to get in on this question.