Firefox don´t render the Font if I change the language of my site.

[lonc...@gmail.com]

This is a very weird problem. Recently I create a blog/site with WP + WPML (multilanguage) for a client, to have his social Icons I use Icomoon free ones. Works perfect but make an strange thing in Firefox after changeing the language of the site, which have two languages, spanish & catalán. If the site is in spanish the icons works but after switch to catalan the icons are broken. What could be ?