Hi again!
We deliberately chose not to include translated pages in one sitemap, because when we do, we should annotate the pages as translated versions. See this issue for more information (there was a lot of noise on unrelated topics in the comments, so I collapsed them).
Since there are so many translation plugins, and also since maintaining compatibility with those bring nightmares, we chose not to take that route. Instead, we rely on the hreflang meta tags outputted on your pages by the translation plugins. This method has proven to work flawlessly.
To add to that, with the help of the translation plugins’ query-alterations, we create different sitemaps for each language separately. On your website, you should be able to access them here:
/sitemap.xml (French)
/en/sitemap.xml (English)
Those sitemaps populate automatically. You can submit them both to Google, Bing, and others, and they’ll use them for crawling.
To close, please note that due to the complexities involved with translation plugins, TSF might not clear the sitemap caches correctly whenever we intend. We added a special case for WPML because it was reliable enough to work with, but for the others, you may want to disable the transient caching for the sitemap. This way, the sitemap will be generated anew every time, which makes sure everything’s included.
You can find the transient caching option at the bottom of “SEO Settings > General > Performance.”
I hope this explains the lot! Cheers 🙂
