watashi wa nihon benkyo shimasu

--> Watashi wa nihongo wo benkyou shimasu. (= I'll study Japanese.) 

--> Watashi wa nihongo wo benkyou shiteimasu. (= I study / I'm studying Japanese.) 

nihon = Japan, nihongo = Japanese language, nihonjin = Japanese people

Watashi wa Nihon go wo benkyou shimasu (or shiteimasu). Watashi no Nihon go wa tadashii ga desu ka?

Good job! By the way, does your computer write Japanese characters? 

Anyway, I hope this helps you. 

watashi wa nihongo wo benkyou shite imasu

Watashi wa Nihongo wo benkyou shite imasu. Watashi no Nihongo ga ii desu ka?