Why are they complementing you?
You will probably have people occasionally compliment you on your language ability. You will want to respond politely. But when compliments come don’t jump to the conclusion that you are doing a super good job.
If you believe what you hear, you might conclude that you no longer need to press on in the language. Compliments may often be an expression of appreciation for your language learning effort and an encouragement to keep at it.
Often the person who uses the language skillfully doesn’t get compliments — his speaking no longer calls attention to his use of the language. By the way, if people give up on you and think you will never get any better, then you will also stop getting compliments.
Brewsters, Language Acquisition Made Practical