When it comes to optimizing a website that targets different countries and languages, the most important rule to follow is that each translation of a page must have its own unique URL. This is to allow search engines to easily distinguish our translated pages and also to let our visitors know that they are viewing the website with a particular locale. As Magento allows us to change the base URL for each of our stores, changing the URL becomes relatively easy to execute. The only consideration would be the format in which we should be configuring our URLs.
Depending on our website setup, the general consensus is to set our base URLs to match one of the following formats: