What languages would you need to speak to communicate with the majority of humans on Earth?

[Alinestra Covelia]

I'm thinking English, Arabic, Spanish, and Mandarin Chinese may be able to do it.

(I don't know if Hindi would be required - India would likely be necessary to get the people count, but how bilingual is the country in reality?)

[Rufus T. Firefly]

You should add French. A surprising amount of the globe is French-speaking. But then you've got it. Hindi and Russian would be the runners-up.

[The Emperor Fabulous]

Probably want to add Portuguese as well. Brazil's a fairly large country.

[duke o' york]

Mime!

[Japher]

Esperanto, Ebonics, and Texan

[Alinestra Covelia]

Esperanto!

"Bonvolu alsendi la pordiston? Lausajne estas rano en mia bideo!"

[snoopy369]

English, Spanish, Mandarin Chinese, and Arabic probably is the best bang for your buck. French certainly is useful but probably is a lower ROI than those 4. I think with India your problem would be too many dialects (far more so than China, iirc, and with far more separation in language). Portuguese wouldn't be necessary because Spanish is close enough that you can make yourself understood.

[GePap]

I would say English, Spanish, French, Mandarin, and then Arabic. The question is not only primary languages, but secondary as well. french is a secondary language to a lot of folks for example.

[Solver]

I think a lot of India isn't bilingual. So let's see, Mandarin obviously gives you China, Spanish would give you Spain and most of South America. If it's communication that counts, not necessarily fully correct and literate speech, Spanish would also give you Portugese-speaking countries because the languages are certainly mutually intelligible. These three languages would probably give you about 2.5 billion people, if you count Mandarin as 1+ billion, English as close to 1 billion thanks to second-language speakers and Spanish would definitely account for half a billion. I think that if you made a cutoff of communicating only with people below a certain age, say, 50, the proportion would rise because young people in the West can communicate in English.

Taking these 2.5 billion, you'd need about another 0.5 billion to make it the majority of all humans. French probably wouldn't do, there's considerable overlap with English speakers. Hindi might bring you close to the 3 billion mark (but I'm not sure how close Hindi and Urdu are), another safe combination would be Russian + Arabic, netting you the former Soviet Union, North Africa and Middle East, probably with little overlap.

[Whoha]

I'm thinking English, Arabic, Spanish, and Mandarin Chinese may be able to do it.

(I don't know if Hindi would be required - India would likely be necessary to get the people count, but how bilingual is the country in reality?)

English, French, Portuguese and maybe German.

[onodera]

I think too English, Spanish, Mandarin and Arabic would be the best combination in terms of population, but what if we think in terms of countries?
Let's say a country counts if it's one of its official languages. Mandarin would probably be useless immediately. RoC, PRoC, Singapore, what else?
English would be my first choice, netting many miniscule Commonwealth countries. Spanish and Arabic would probably stay, too. What other languages do we need to get 102 countries?

Edit: Actually, we need to add French. It is probably spoken in more countries than Spanish.

[Krill]

Please could you send for the hall porter? there appears to be a frog in my bidet.

[Unimatrix11]

Well, if you want to ba able to speak to all people, then you´d have to add italian as well, cause they dont speak anything else (in my experience)...

[Solver]

Counting in terms of countries is probably less useful. But that's easier. English gives you a lot of countries, some small Oceanic ones, some African countries and, IIRC, Pakistan. French would cover a lot of Africa and Spanish would cover a lot of South America. And Arabic of course. But I think that would be the end of efficient languages for this purpose. Too many countries that have their own language as official.

[onodera]

Well, if you want to ba able to speak to all people, then you´d have to add italian as well, cause they dont speak anything else (in my experience)...

Some of them do speak English, but I find their accent hilarious. Only some Indian accents (where they replace final T's with cork popping sounds) are funnier to my ear.