Finally Shopify are starting to catch up with the needs of it's ever growing merchant community and now allow you to serve your store in more than the base language of your store. Here's how.
Each language has it's own path, besides the base language which sits on the root domain. For example, if your base language is English and you have enabled French and German you'd end up with this set up:
All paths remain the same, just sitting under the sub-folder:
1. Head into the Settings page and click "Store languages":
2. Click "Add language" and choose whatever language you'd like to serve. Do this for each desired langauge:
3. Translate your theme. This might be the job for a professional, or you can do it yourself. If you've never manage a language file in Shopify before then check out Shopify's article on this.
4. Publish the languages by making your way back to the language settings and clicking "Publish" on each language that's ready to go under the "Unpublished languages" section: