Which world language is as important as English?

What non-English language will be most useful for my child to know in 20-30 years?
French? German? Arabic? Chinese? Spanish? Something else?

Why?

I'm going to disagree with all the answers for Mandarin. The reasons given for Mandarin are basically correct, and by no means will it be a bad language to learn.

However...

While a very large number of people speak Mandarin, those people are mostly in China. Of all the countries in the world, Mandarin is only an official language in China, Taiwan and Singapore. English is the most common foreign language in China, and is also an official language in the Chinese special administrative region of Hong Kong. Also, while Asia will likely remain the most populous region on the planet through the next century, the percentage of the world's population found there will drop, because of growth in Africa, and, to a far lesser extent, in Latin America and the Caribbean.

French is the official language in 32 countries, 21 of which are in Africa.

Arabic is the official language in 24 countries, 12 of which are in Africa.

Spanish is the official language in 22 countries, 20 of which are in Latin America and the Caribbean.

Portuguese is the official language in 10 countries, 6 of which are in Africa, and 1 of which is Brazil.

Unless my goal were to specifically work in China, I'd focus on these languages, in this order.

Source: https://www.quora.com/What-non-Engli...in-20-30-years


Neteller here: www.ituglobalfx.com.ng