SharePoint Online for a long time, has multilingual support. On classic experience, there were language packs and Variations available for that. Yet also the modern experience has multilingual capabilities for that.
It might look that SharePoint is well capable of providing the language chosen by the user for the user. While I had to take a closer look under the hood over the last couple of month, multilingual and SharePoint has a complicated relationship.
Recently a new feature has been added to the authoring process in SharePoint online. This new feature helps you to define appropriate alternative text descriptions for your images on pages. In general to specify alternative text for images is possible the first time in SharePoint history. Previously only the title of an image could be defined.
When a new image gets inserted on a page, the image gets analysed by a background service, which assumes the content of the image and returns an appropriate description. Through the help of pattern recognition and artificial intelligence, the returned values are pretty accurate, at least with the pictures I tested this feature so far.