Depending on the language you’re learning, you’re going to receive compliments for your skill.

Those of you who were good little children and obeyed your mothers growing up are going to turn down each compliment:
“No, no; I suck; I’m terrible.”

The arrogant will be insulted by the compliment.

In my book, arrogance beats humility, but in the end, neither of these reactions help. In any case, let’s address humility, because it’s the most socially acceptable (and thus most potentially damaging (insofar as no one is going to call you on how much damage it’s doing) reaction):

People went out of their way to compliment you. Take the far king compliment. As a semi-frequent compliment-giver, I hate it when you compliment a girl, and you tell her she’s good lookin’ in the face and derrière (but dumb as rocks) ¹ and she pulls a Consuela from “Family Guy” on you.

Don’t be humble like that. The next time someone compliments you on your language skill, do two things:

1. Be arrogant. Yes, arrogant. Be amusingly, OTT blunt and arrogant. Say “yes, I know”, or “I KNOW, RIGHT?!”, but also
   1. Extra points: Return a compliment that makes no sense, like: “you are also very good at Japanese, Mr. Person from Japan”.
   2. It’s funny because…yeah.
2. Ask for corrections preemptively if you say anything wrong: “Please correct me if I make any mistakes”.
   1. Presumably the compliment has come from someone who knows the language better than you. If not, don’t bother with this stage

And then keep being arrogant and confident, but gratefully take the correction if and when it comes. It’s like getting free teaching that actually helps. This mix of humor, arrogance and a sincere request for useful information is called: scrappiness. Like Scrappy-Doo, Scooby-Doo’s nephew. Any time you see new words, you’re all: “Lemme at ’em! LEMME at ’em!”

Humility knows its place.
Scrappiness — pluckiness — changes its place, and isn’t afraid to get help doing so.
Humility admits it sucks.
Scappiness is not content to suck, always improving.
Humility wants to be a good person, to look good.
Scrappiness wants to do better, to be better than before.

Don’t be humble. Be scrappy. Don’t “know your place” — be too busy improving = changing your place to know. You shouldn’t know what your level of Japanese/whatever is. You should have too much momentum to calculate your position.