That depends a lot on your niche and the type of information that you provide.

For example, for a standard 10-page service website, it's best to have a local version targeting your main locale groups. It gets much more complicated if you run an online magazine - imagine having to translate your 30 news entries a day in 12 more languages.

Also, specific industries and expert-based websites tend to be English-only since the audience is expected to communicate internationally anyway (Clarity is a similar example). If you're looking for a broader audience, then consider translating your content (SEO is also a plus which was outlined above).

As a final note, some countries are skeptical to any foreign languages while others use English as much as their native one.