Links to the Apertium website such as the ones on Wiki's frontpage are structured like http://www.apertium.org/?id=translatetext&dir=oc-es. The two parameters are completely ignored by html-tools and the user always arrives upon the same interface. However, there should be support for something of this nature with a URL like http://www.apertium.org/?pair=oc-es#translation. Another URL parameter that needs support is ?lang which should switch the interface language.
Diff:
Addressed in r52340 (?lang) and r52299 (?dir), needs to be checked.