Really, truly, sincerely make an effort to learn a foreign language. You want to gain a bit of conversational ability in a foreign language, at minimum. This would equate to being able to haltingly speak to a foreigner in their own tongue, perhaps: your speaking ability might not dazzle anyone. But the benefits of being able to go to another country and understand the street signs and order lunch and communicate with strangers (however rudimentally) are numerous.
Not only are there practical aspects of learning a foreign language (when traveling), but there are immeasurable intellectual benefits as well. Knowing another language is an important skill to learn aside from it’s social and/or business benefits. You expand and exercise your mind by speaking, hearing, and thinking in another language.
It’s not unusual for people to speak more than one language in Europe or the Middle East. In America, however, people tend to only speak English. This can be limiting, and there’s no excuse for it. A man is much more well-rounded as a person and better-equipped in business and social scenarios when he is multi-lingual.
Thomas Jefferson read a number of different languages. In a letter to Philadelphia publisher Joseph Delaplaine on April 12, 1817, Jefferson claimed to read and write six languages: Greek, Latin, French, Italian, Spanish, and English. After his death, a number of other books, dictionaries, and grammar manuals in various languages were found in Jefferson’s library, suggesting that he studied additional languages beyond those he spoke and wrote well. Among these were books in Arabic, Gaelic, and Welsh. (Source)
There is no one correct way to learn a new language, so you may have to find what works for you by experimentation. Trying something – however imperfect – is better than doing nothing. I started learning Spanish by making an effort to meet the Latina girls and simply asking them to teach me some words. (I also studied vocabulary in my spare time by making my own flash cards from looking up words in a English-Spanish dictionary.) You can probably do better, by reading a good book on how to learn a language (like this one), using an app, and joining a meetup for the purpose of practicing.
However you choose to do it, as a complete man you should learn a foreign language.