Steps:
1. Download Zend Cart language pack, you can find packs here
2. Find folder languages in your account, usually it is /public_html/includes/languages/ or /www/includes/languages/ via File Manager or FTP, and upload your language archive there
3. Extract all files from the archive into languages folder.
As an example there should be:
/includes/languages/english
/includes/languages/french
/includes/languages/german
4. Then enter into Zen Cart admin panel (http: // yourdomain . com / admin / ) and follow
admin > localization > languages > new language
That’s all folks