Vocabla for Firefox can translate English words using double-click. This plugin translates words from English to Spanish, Polish, and English definitions. You read and find new English word, double Click on it, and you get Translation.
What's new in version 1.5
ReleaseApril 25, 2013
Date AddedApril 26, 2013
Operating SystemsWindows 2003, Windows Vista, Windows, Windows 7, Windows XP