A critical component of preparing for travel is figuring out whether you can understand the people and places to which you’re going. If you’re an American and speak English, odds are in your favor; the dominance of England and then America in world events means that, as the dollar is the standard against which other currencies are measured, so English is the go-to language, and many people outside of English-speaking countries learn English to facilitate their own travel.
The downside of this is that it discourages those in English-speaking countries from learning other languages, since they feel they don’t need to. This is a cultural tragedy. Learning another language not only provides access you cannot get otherwise, although it certainly does that. Learning another language also provides cultural insight that you will never get from a cultural sensitivity class.
Most people don’t realize how much language shapes how they think. Any student of languages knows, however, that not only is their variation in such relatively superficial things as the types of words for objects, but there’s also serious variation in the process of describing things, of speaking in tenses (such as the past or future tense), and even in basic sentence construction. People say that you know you’ve really learned a foreign language when you start dreaming in that language; certain types of language facilitate certain types of thinking.
As such, it is worthwhile for those who wish to understand other cultures to study their language(s), whether it’s technically necessary or not. This may also develop further appreciation of their own language, and their own culture.