Linguist David Crystal, who has surveyed world use of one or another "interlanguage" for official use by international organizations, has found that actually most frequent and most exclusive use of English as an interlanguage is in east Asia. It is remarkably "natural" for a Korean person to try speaking English to a Japanese person (even though Korean and Japanese are cognate languages), and it is more expected still for a Chinese person to speak with either of them in English. What I find remarkable, but have observed more than once, is speakers of different Sinitic languages ("Chinese dialects") speaking to one another in English. Online, which is mostly the context Jeff is talking about in his blog, the early inconvenience of typing in the CJK languages (now resolved, as an in-country issue, but still a big barrier to switching among those languages) resulted in much Internet communication in east Asia being in English by default.

After edit: France was mentioned in the reply above to which I reply here, and I'll mention that the Carrefour retail chain has stores in Taiwan, and the signs inside the stores are in Chinese, of course, but also in English, NOT in French. There is no reason of national pride among the Carrefour staff sufficient to overcome the practicality of using English to reach customers in Taiwan. (Taiwan has a large population of English-speaking foreigners, the plurality of whom are Philippine guest workers.)

At least with the limited contact I've had with Chinese and Japanese developers the level of English wasn't particularly high, so I guess I'm a bit surprised by that. In the Chinese teams they even went as far as to try to suck in someone from Hong Kong so that he could be the bridge between the Chinese and German (the team I was on, though communicating in English) groups.

As to the observation of different Chinese dialects using English as an interlanguage within China (...I assume you didn't mean within China)...this is probably very rare. In my 9 years of living in China mingling with all sorts of regional and ethnic groups, I have never once seen this happen.

Now, given that a Japanese and a Korean are to communicate, of course it's more likely that they will do so in English.

Small countries like Iceland, the Netherlands and Denmark can't possibly expect anyone to learn their petty language that can't be used anywhere else, and thus realise that they have to learn English if they want to communicate outside their borders.

Edit: Interesting note -- if Dutch, Flemish and Afrikaans are all considered the same language, then Dutch has around 30 million native speakers.

Bjork does sing in English though :-)

When working in japan, none of my japanese coworkers could speak or read english (even worth than France...) and they only read translated programming books with a 6-12 month latency to get new information....

Now if I hired programmers, I would never hire someone who doesn't read english fluently because I believe that someone, who is truly interested in programming, will try hard to learn English so he can access to the quantity of knowledge written in English.

But your last sentence seems really harsh. Good communication skills are so much more important in real life to have work done.... I know a few good programmers in France for whom reading english is a lot of (sometimes necessary) pain. I'm sure more contacts with foreigners would give them a incredible confidence/motivation boost.

A big advantage you have as a local developer over an Indian developer is that you speak the native language of your customer. It seems kinda silly to throw that kind of an advantage away.

Besides, you can't really apply the principles from Domain Driven Design if you translate everything to English. You would end up with one language in your code and another language to talk to your customers, instead of a single ubiquitous language. This becomes especially difficult when you have a complex domain with tricky business rules that requires frequent collaboration with domain experts.