A free program for Android, by AllDict.

This free and easy-to-use dictionary is designed to assist you in learning and mastering German and Russian, the most common languages in Europe. It provides you with all the necessary information, from which you can also listen to the pronunciation. You can add words to your personal dictionary to help you memorize them.

With the word trainer, you can practice all that is necessary: your pronunciation, your reading skills, and your writing skills. The word trainer also has different exercises to make you practice all of these skills. 

This makes the app a very useful and indispensable tool for learning languages.