Manually translate in prestashop 1.6

Click on Localization > Translation
menu

On Modify Translations Segment.

modify
1. Choose Type of Translation = Installed modules translation
2. Select your them
3. Select your desire language

and click on modify icon on right side.
trans
Now you will find module’s wise translation. In left side you will get english langage. An in right hand side you will have to translate manually.