One store - multiple domains SEO

[Bikerapparel]

Hello,

We recently created one store with international domains. So, we have different languages for each store, for France - French only, for Spain - Spanish only, etc.

Is there any way that we can add alt texts in different languages? Now all the alt texts are in English, as the main domain is in English (.co.uk). Can you suggest any other way so we can optimize the website in different languages? 

Thank you!