Oh, I certainly didn't say there is no value in knowing more
languages. But the added value of knowing more goes down
quickly. That is, you get more value out of knowing your
first language than out of knowing your second, which has
more value than knowing your third, etc.
I also made the exception for "small domain" languages.
Languages that are suited to do a specific task very well.
Examples of "small domain" languages are TeX, sed,
sed, gnuplot, but also "languages inside languages", like
printf formats, pack formats.
Maybe it's just the way I work, but generally when I need to
solve a problem, I first think up an algorithm, and a general
outline of the program. Only then I write a program. It will
mostly be in Perl (because that's the language I like), but it
will lead to a similar program as the one I would have written
in, for instance, C. Details will certainly differ, but not