Isn't this open source? anybody can rewrite the code in any language that they want.
It definitely *is* open source but not just *anybody* can rewrite the code - to do that you would need to understand not just the C++ language (which I don't think anyone here is arguing is easy itself) but also boost (a big library which I actually don't use) as well as the other libraries that are being used in the project.
Even the devs themselves missed the subtleties of BerkleyDB that led to the temporary "hard-fork".
In short - no-one is going to come up with a 100% compatible Bitcoin equivalent in another language without a *lot* of work (a point that has been argued in various other threads - the problem was that Satoshi wrote the spec *after* he wrote the code).