This is the 10300th most frequent Polish word.
chińsku
"Chińsku" means "Chinese" (in the manner or language of China).
Here, 'chińsku' is used as an adverb to describe the manner in which the subject speaks, indicating the language.
Mówię po chińsku.
I speak Chinese.
Here, 'chińsku' is incorrectly used and should be replaced with the noun 'chińskiego' to correctly state this.
Nauka języka chińsku jest bardzo trudna.
Learning the Chinese language is very difficult.
'Chińsku' functions as an adverb, modifying the action of writing to specify the language used.