I think the most successful tack is the one that encourages someone to investigate, not because "mine is better", but because "different is enlightening." Here's a quote I happen to like:
Thoughtlessly applying techniques effective in one language to another typically leads to awkward, poorly performing, and hard-to-maintain code. Such code is also most frustrating to write because every line of code and every compiler error message reminds the programmer that the language used differs from the old language. ...Every language can be a fertile source of ideas... However, ideas must be transformed into something that fits well with the general structure of [the new language] in order to be effective in the different context.
The C++ Programming Language, Special Edition.
My feeling is that most of the time when people are quick to dismiss another language it's because they haven't learned enough from it to get past the stage of "thoughtlessly applying techniques effective in one language to another", and are frustrated because "every line of code and every compliler error message reminds the programmer that the language used differs...". Given a chance, most languages have at least something to offer. I think Perl has a lot to offer to those who are willing to work past the awkward stage.