@Tutanota For #fediverse software and apps with #language filters, I suggest you do not mix languages in one post as it will more likely be filtered out.
Also, since you are in a #Mastodon instance, it has a “posting language” feature. If you post in English, select “en”, if you post in German, select “de”. Which also helps in filtering posts if it is supported by your follower's fediverse platform or app.
Of course, it's all up to you, whichever posting strategy you choose. I think it's safe to assume that there is a very low number of users who filtered out English, if any. ^_^
@youronlyone Tried that, but people complained they did not want to see German posts. (maybe they did not set up the filter on their end)?