Do you mean language of User Interface?
Every iPod sells in Word-wide comes with Built-in Multi-language User Interface
No matter you buy it from U.S or J.P, it would have both T. Chinese and S. Chinese.
If you mean Subtitles of Videos, if the subtitles is built-in on the video itself, then it doesn't matter what language is it, it is being treated as part of the video pictures itself.
The New Flying MacBook Pro; Seatbelts sold Separately!