It's not unreasonable when it's written in the official language of the country in which your office resides.

Since they know that the employee didn't speak the language, they could have provided him with an English translation of the contract (specially since the startup is itself a translation service).

To be fair, the employee should have asked for a translated contract upon being presented with one in a language that he doesn't understand.

So it all right to rip of foreigners then or people not versed in employment law.

Foolish or badly advised people still have rights you know

A foolish person would sign a contract in a language that they can't read. No reasonable employer would be offended if you refused to sign an agreement you couldn't possibly understand.

If they were offended, that would be even more of a reason not to work there or sign it.