Not only are there some strong NLP people in the Perl community, but the language was designed by a man educated as a linguist. The initial role of Perl was text processing. It has grown well beyond just that, but it still handles text better, faster, and more comfortably for the programmer than many other languages.

I'm not personally very well versed with the linguistics modules on CPAN, but I've heard very good things about some of them. I've looked briefly at several because they fascinate me (I intended to be a linguist myself at one point), and I can tell you there's much more value on CPAN for NLP from what I can tell than there is out there for PHP. In the interests of full disclosure, Python and Java also seem to be well-represented in the NLP arena, though.

As long as you're looking at alternatives, I'd suggest looking at http://opennlp.sourceforge.net/projects.html, where a number of Open-Source NLP packages are described.