Which languages you translate your documentation into is a function of your business objectives. This sounds straightforward enough, but the problem arises when you’re not sure whether your potential Chinese customers prefer Simplified or Traditional Chinese (see blog entry on Chinese), or when your South American manager insists on having a “localised, Latin American” version of an internal newsletter which has already been translated into European Spanish.
The greater your understanding of languages and language variations, the easier these decisions will be, and you will get this by asking for professional advice from linguistic experts (your translation company) on the one hand, and your internal customer on the other.
Bear in mind, however, that most people will consider their own language variation to be “correct”, “the most prestigious” or “the most neutral”. Fortunately, for a broader and more objective perspective you can turn to a team of professional linguists.