Stardict is one of the best free dictionary program in Linux and Window. It offers many dictionaries in different languages. And all of them are free!

You can download stardic here

http://stardict.sourceforge.net/download.php

Download dictionary files here:

http://stardict.sourceforge.net/Dictionaries.php

To make Stardict pronounce English words you may use WyabdcRealPeopleTTS package. Download it here:

http://prdownloads.sourceforge.net/stardict/WyabdcRealPeopleTTS.tar.bz2?download

For Linux, copy WyabdcRealPeopleTTS.tar.bz2 to your home folder, then use those command:

sudo cp WyabdcRealPeopleTTS.tar.bz2 /usr/share

cd /usr/share

sudo tar -jxvf WyabdcRealPeopleTTS.tar.bz2

Configuration: Preferences -> Sound at Command for playing wav file: type mplayer -ao alsa

Install mplayer with:

sudo apt-get install mplayer

For Windows, you can simply use WinRAR to extract the it and install it at “C:Program Files” or “Program FilesStarDict”.

Enjoy!

Updated Nov 5th, 2009:

Try Qstardict! It is similar to stardict.

Download dicaionaries:

http://stardict.sourceforge.net/Dictionaries.php

http://sourceforge.net/projects/stardict/files/stardict-dict-babylon/

Give normal user permission to write
sudo chmod a+w /usr/share/stardict/dic
Untar and move dictionaries to “dic” directory
tar -xjvf a.tar.bz2
mv a /usr/share/stardict/dic
How to make qstardict pronounces words with WyabdcRealPeopleTTS

http://wiki.qstardict.ylsoftware.com/Pronouncing_words_with_WyabdcRealPeopleTTS