Which foreign language will be most valuable in the next 20 years?

[Schmedlap]

Good feedback.

The Chinese and Indians can often communicate in English... Correct writing in foreign language isn't essential and deserves no emphasis in military language training.

Not Hindi

Almost everyone in Pakistan speaks English... Pashtu is ethnocentric...

Not Urdu
Not Pashtu

one can argue that Arabic is now a global language due to the global distribution of Islamic schools funded by NGOs from the Middle East).

Arabic, check

... since India has several languages, to include English I wouldn't invest too much time learning Hindi.

Not Hindi

... learning a second foreign language is easier than learning the first and the ability to operate cross-culturally tends to transfer from one area to another.

WILF - I feel your pain. I did the Serbo-Croat thing. At the time, I couldn't find many resources to learn it, so I also started learning Russian, which was similar and far easier to find materials for. Then 9/11 happened. But, as John points out, the process of learning Cyrillic script was a helpful experience when I started learning Arabic script. Kind of a funny story there - one of our interpreters knew how to speak Arabic, because he learned it growing up in the US, but he never learned how to read or write it. A few of us could read Arabic script (though we didn't know what the words meant). If we saw some graffiti we would take a few tries to sound it out because there were no diacritical marks. After a few stabs at reading it, guessing at the vowel sounds, we would stumble upon the right pronunciation and then the interpreter would tell us what it meant (usually nothing significant - "Ahmed loves goats" - nice, we'll pass that on to the S-2).