If I say stuff like: Я немного говорю по-русски , russians will underestimate my russian language skills and will resolve to speaking with me their bad English (which is worse than my russian!), or their bad Hebrew.

If I say я знаю русский язык, they will overestimate it and use big words, slang, and talk really fast that I'll start missing whatever they're saying.

I was thinking of я знаю русский язык так себе... is that good? Or any other alternatives I can use?