tusind tak!!

It can mean a lot of things, but normally used in the spoken language about learning a certain skill/competence on your own. Like a appreciation/confirmation that you learned7gained this skill/competence. 丹麦语有点困难，因为我们使用有很多主题的话。 Tilegnelse经常用于你自己学到的技能。 像确认和/或欣赏。

Literally, tilegnelse means making it your own. The full meaning is, that you are good at learning Danish, and that you remember and can use, what you learned. The word is only used formally in contexts like this. It can also be used informally in other contexts, like: "He stole my wallet"; "Han tilegnede sig min pengepung." = "Han stjal min pengepung"

Here “tilegnelse” can be translated with “acquisition”. It means “the acquiring of knowledge or a skill, typically through tuition/instruction”. To me, without more context, “Din tilegnelse af dansk er god” is ambigious and it’s not something I would myself ever say. It literally means “Your acquisition of Danish is good”. It’s not clear to me whether it means that “you” have reached a good level of Danish or that you’re making good progress in learning Danish.