English is a great 'utility' language. It's easy to absorb new concepts into it, and it is very widespread so there's a good chance someone wherever you are knows at least enough to be useful in communications. So, as a business language, English is probably one of the best if not the best.
In terms of detail and nuance, english is a poor contender. Many other languages allow for finer subtleties and concise shades of meaning. This is part of the reason why it's so difficult to translate non-english literature to english and why so much gets lost in translation.
I guess it depends on what your use is... if you want to order a bigmac anywhere in the world, chances are english will do the job. If you're trying to get laid, english may be a poor second choice.
