If you're planning to submit a theme to the Shopify Theme Store, it must be internationalized.
What's an internationalized theme?
An internationalized theme is a theme that enables merchants to use the Shopify Language Editor to translate their storefront content into another language.
Optionally, an internationalized theme can also include ready-made translations in one or more languages. Merchants can choose any one of these supported languages and activate it on their storefront immediately.
What must I include in my theme?
To meet Shopify's standards for internationalization, your theme must:
- include a locale file for each language that your theme supports, containing all the translated content including checkout and system translations if necessary
- replace all the hardcoded website content in your theme template files with translation keys
- implement a translation filter in your template files, to pass the translation keys to the locale file.