Do we have to have a second language? As a Japanese individual, why do we need to learn (for example) English?
How about Spanish?
According to "Statista," based on their statistics, "In 2017, the most spoken language in the world was Chinese (1.284 billion), Spanish (437 million) in second place, and English (372 million) in third place."
Personally, it's better to learn more than two languages. If I have enough space inside my brain, I would definitely try to learn Spanish.