TranslateIt

TranslateIt is a dictionary for Mac to translate words between different languages on the fly, including English and Spanish. It works with all applications developed with the Cocoa framework.

To translate a word, just hover your mouse over it until a small drop-down menu appears with the equivalent term in another language, some synonyms, and common expressions in which it is used.

By default TranslateIt comes with several dictionaries, including English and German, English and French, English and Russian, and English and Spanish.

The application also has a voice synthesizer to pronounce unknown words for users upon request.

With this application, you can translate a word instantly just by double-clicking it, right from your clipboard, by dragging and dropping the word onto the application, or by entering it manually.

On the TranslateIt website, you'll find dozens of dictionaries you can add to the application to increase the number of available languages.