English is, as far as I know, the most used language to communicate in the internet. Due to the fact that English is also often used by scientists, the internet was from sratch on in English. I would suggest that other languages came later, with the increasing number of normal users.
And I think for this reason, the Internet talking English, English will be the most spoken language instead of Chinese by the time global access to the web has increased.
But back to typing: I had recently a few chat conversations in French and I wrote mails in French. And it was much more difficult than writing something in English (not to mention German). Of course, my French is ways worser than my English. But this is just one reason.
Unlike English French has a variety of special characters, like à, é, è, â, ô or c with a cedilla (I would need the windows charmap to show it – I think with a German keyboard configuration it's not possible to insert it). And I think most other languages have those special characters with Macrons, Carons, Cedillas or however you call these little additions to a regualer character. Scandinavian languages have it (I learned Finish for a while and it was very annoying to learn it due to these characters), Latvian has quite a huge number and you could long this list as long as you want.
German, has some special characters too, for example ä, ö, or ü. Although, I can type these characters as easy as any other. But of course only because I'm used to it. I don't know, how difficult are these characters for non native speakers (writers)? Maybe with another keyboard language? I don't know if similiar conventions exist in other languages, but in German you can alternatively use ae instead of ä, oe for ö and so on which solves the problem.
English is an easy language. And the lack of special characters makes it even more easier. Any keyboard in the world should be usable to type English without having to change the keyboard language. (Don't they? I don't know how Chinese keyboards look like ;-) ) I didn't tried it yet, but I am very excited how easy/difficult it'll be to type Latvian.