If Daniel Tammet memorize a language in a week then why he does not learn more languages?

Question

For example.chinese greek russian etc

Answer 1

I like LJ's answer....but I have a simpler one.

Just because you can, doesn't mean you should.

Answer 2

I have done some research, posted below, and this guy already apparantly knows 11 languages. Isn't that enough? Besides, he dosn't seem to be the kind of person who needs to know all of this as he is most likely someone's dependant. And, of course, there is also a possibilty that there is a limit to what he wants to do, i.e. why dosn't he sit down all day and calculate pi?