At the last time i trained my brain with perl. I am in love with perl. Perl plays a nice role in the finance sector. So i switched my stuff from matlab, python and co ... completly to perl ...
Perl is nice and has a great repo (cpan). You can easy connect to apache and friends. You can do easy MVC (model view controll) with perl and php. If you wish, you can embed to c++/c# or java as an nice scripting / data language.
If you like java and tomcat, you can use JWt, Java Web Toolkit ( and perl.
Perl has a nice collection of books and good tutorials. You can easy adapt from matlab or r with the PDL (.
You can easy scrap content or data with perl or use Finance::Quote. You can charting with GD or use Perl easy with flash.
With DBI you can easy access databases and execute your statements ...
If you need indicators, there is a modul for TA-Lib or use Math::Business. IMO Perl is nice for "light" HFT ...
All in one Perl is a powerful machine learning language and easy to learn and use ...