While it is useful for many people there is a problem with automatic language selection.
Upon installing version 2.7.6 I was surprised to find avidemux unreadable (French).
How it works is unclear for me, I think it searches for the system language, but there it failed.
In my case, I live in Belgium.
In Belgium there are 2 main languages: French and Flemmish (Dutch), and a bit German aswell.
Dutch is the main languange of the Netherlands, which is a neighbour country, but that is a whole other discussion lol. Flemmish and Dutch are very much alike.
The same way as English and American are much alike.
So in the settings (MacOSX) for region there is Belgium, for preferred language there is Dutch (Nederlands). And if I'm not mistaken, the keyboard is a French layout.
I hope this helps a developer of avidemux.
Maybe the easiest solution would be to make a statement, when firing up avidemux for the first time, that other languages ARE available in the settings, but NOT automatically change it into what avidemux thinks it is.
Now I HAVE to admit that upon checking my MacOSX settings somehow there was, besides my main primary language, French and some sort of Chinese. I don't recall me chasing those languages, so I have absolutely no idea as to why they where there.
Avidemux obeys the environment variable LANG as set by locale, but no Dutch translation exists (neither for Avidemux, nor for Qt which Avidemux uses as graphical user interface toolkit), so
in the Terminal should launch Avidemux with Dutch GUI, but due to lack of translation it will launch in English. "Avidemux_2.7.7" is not a typo: an update to a recent nightly build (https://avidemux.org/nightly/osx_catalina/) would be highly recommended, 2.7.6 is very outdated.
I don't think it might pose a problem, at least in Europe, to press "Command + ," and to select English from the dropdown menu.