Let me tell you about Etranslate, a great translation app - clean interface, friendly support, cost-effective and easiest-to-use translation service in the platform. Manual translate & automatic translate are both available, and Import/Export.
MotaWord is a Shopify-based, easy and helpful translate tool helped many merchants translated their store into multiple languages.
But don't take my word for it as I am biased (I am one of the team). Just try it for yourself.
If you have any questions, just let me know.