Thank you Stefano for your reply.
Here's how I was trying to explain this issue to Valentyn (WP Multilang, developer). Maybe you will better understand...?
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I just wanted to let you know, in case you have a clue, that Newsletter plugin seems to have a problem when creating an issue to send.
Ex.: All my articles are available in both languages (FR + EN).
When I create an issue, the system always pull only the French content. It never pulls the English.
A clue: when I first install this WordPress, I installed it in French, then I added the English translations to my contents.
Let's meditate on this... 😉
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Kindly,