Langtolang Dictionary Sidebar Widget for WordPress provides a multilingual dictionary translating from/to English, Arabic, Chinese Simplified, Chinese Traditional, Czech, Danish, Dutch, Estonian, Finnish,
French, German, Greek, Hungarian, Icelandic, Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Norwegian, Polish, Portuguese Brazil, Portuguese Portugal, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Turkish from the wordpress sidebar.

Visit http://www.langtolang.com/external/wordpress/ for more information.