Translating your product pages isn't enough. A customer from abroad who adds an item to the cart must stay in their own language all the way to payment. That's where most shops lose them.
Where a customer lands back in the original language
The “View cart” button that leads to the cart in the original language (/cart/) instead of /de/warenkorb/.
The cart and checkout, drawn by the shop's scripts: product names and their options often show up there in the original language.
Shipping and payment methods: “Free shipping”, “Direct bank transfer”… saved in the shop settings, in the original language.
A customer who sees a language they can't read come back just as they're about to pay hesitates, and many stop there.
