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The most useful language for English speakers to learn, according to an economist

People walk over a world map engraved in marble in Lisbon September 14, 2011. Global markets have been roiled since the end of July by…
People walk over a world map engraved in marble in Lisbon September 14, 2011. Global markets have been roiled since the end of July by…
Image: Reuters/Jose Manuel Ribeiro

Dear Emily,

I’m gearing up for my freshman year of college, and I’m trying to decide which language to study. I’d like to pick the language that will be most useful and practical in the years ahead. If you had to pick just one, which would you recommend?

-Freshman

Dear Freshman,

As someone who took six years of Latin, I am not sure I am the best source for information on what language will be useful and practical, but I’ll give it a try.

First, let me say I don’t think you are thinking about this quite the right way. You asked me about what language would be most useful. This suggests you’re thinking about only one side of the choice: the benefit side. Making the optimal choice requires thinking about both benefits and costs. In this case, I’d argue there may be very different costs to acquiring proficiency in different languages. It is a lot harder for most English-speakers to learn Japanese than to learn Spanish.

But let’s start with the benefits. The benefits of a new language arise from the new people you can interact with in your new language. If maximizing this was your only goal, Mandarin would be the best choice: This is the native language for 14% of the world’s population, and most of those people do not speak English, so it’s all a win.

A somewhat distant second to this is Spanish, the native language of 5.8% of the world’s population, followed by English (which you’ve already got covered), Hindi, and Arabic.

You might also be interested in considering how influential a given language is likely to be in the future, based on an area’s anticipated economic growth. Mandarin retains an advantage here, given that China is both (a) important economically now and (b) likely to be even more so in the future. Spanish has the advantage of being spoken in a larger number of countries, although the total GDP of these countries is less than half that of China alone (roughly $11 trillion in US dollars). On the benefit side, I think we’re down to Mandarin and Spanish, with Mandarin having the advantage.

On the cost side, you face some clear tradeoffs. Mandarin is a difficult language to learn, particularly as an adult. Learning to say “Ni Hao” and “xiexie” will endear you to a few locals in Shanghai, but it’s unlikely you’ll get far enough in Mandarin to find your knowledge of it truly useful. By contrast, Spanish is considerably easier for native English speakers, and it’s a lot more likely you’ll reach some level of mastery. In the end, I’d say unless you are a truly gifted linguist, Spanish is the most practical choice.

Of course, if you want something which is really useful and practical, you might consider a new computer language, instead. I hear good things about JavaScript.

Emily Oster is an associate professor of economics at Brown University and the author of “Expecting Better: Why the Conventional Pregnancy Wisdom Is Wrong — and What You Really Need to Know.

Got an everyday problem that could use an economist’s point of view? Send Emily your questions at askemily@qz.com.