If someone has a goal to learn languages because of personal career choices such as being a translator or interpreter then it would be better to learn various languages. However being proficient in one language is much easier and still holds multiple benefits as well. Some companies do look into how many languages one knows but most companies are not interested in how many languages you know If they won’t be able to put them to use. The wise thing to do is look at your goals and see what benefits you more as an individual. Whether it is being able to expertise in a second language or element in various languages.