"I think I'm pronouncing this French word wrong."
Translation:Je crois que je prononce mal ce mot français.
Initially I started to put that too since that's more the literal translation from the English, but then it occurred to me that if I put the word 'mal' after the noun object "ce mot français," then I'm really putting 'mal' with that object and not with my pronunciation of the word, which is really what 'mal' is qualifying here. The "mal" really goes with the verb as an adverb, so it makes sense to put it with the verb, i.e., "je prononce mal." If you think about it in that way it makes more sense. Otherwise, the "mal" would be qualifying the word as if the word itself was bad. Make sense? :-)
That is a very simplistic way of looking at it.
You are not likely to be expressing an idle thought about your own prononciation. It is much more likely to be something that you believe to be true of your own prononciation.
Hence, "croire" is the better choice (and the natural choice of a native speaker).
Initially, Duo did not even consider it necessary to include "penser" as a possibility!
Nope, either "wrong" or "wrongly" is fine. Merriam Webster says "wrong" can be an adverb. https://www.merriam-webster.com/dictionary/wrong -- and so does Cambridge Dictionary for British English https://dictionary.cambridge.org/dictionary/english/wrong?q=Wrong
You'll be suggesting that we should be allowed to drop "ne" and elide "tu" next!
It's bad enough that Duo has not yet completed the eradication of "kids".
Informal speech is one thing, a certain amount of informality is a good thing, but informal vocabulary is not appropriate.