how do u say: i can speak 4 kinds of language in japanese?

Literally,

私は４種類の言葉を話すことができます。
Watashi-wa yon-shurui no kotoba-wo hanasu kotoga dekimasu.

More naturally,

私は４カ国語(を)話せます。
Watashi-wa yon-ka-koku-go-(wo) hanasemasu.

----
Watashi = I
-wa = subjective case
yon = 4
yon-shurui no kotoba = 4 kinds of language
yon-ka-koku-go = 4 languages
-wo = objective case
hanasukotogadekimasu, hanasemasu = can speak

watashi wa yonkakokugo wo hanasu kotoga dekimasu.

watashi = i
yonkakokugo = 4 kinds of language
hanasu = speak
dekimasu = can

Just say;"I can speak 4 kinds of language in Japanese"
See, very simple!