This is really difficult. You have to hire professionals to translate websites for you. Don't rely on Google or any other free service as it's very bad.

Take Chinese for example. Google said they support both Simplefied and Traditional Chinese, but visit any Chinese website and you'll see how much Google supports, which is nearly nonexistent.

Other non support language such as Vietnamese, good luck. To my knowlege there's no service that can translate English to Vietnamese and vice versa. Even if there were, the computers are still too stupid to know grammar in every language (it has a hard time enough to understand English already).

If you truely wanted to take your website internationally, just keep in English is sufficient. Hire professionals to translate into Chinese, Japanese, French, German, Hindi and Spanish is probably enough.