I just found out running the installer in virtualbox for screenshots (normally I don't give a shit and click onward w.o reading) that:
The live USB starts of in the language my IP is based in. That seems like a nice automation but it is not ! Especially when using a VPN.
It should not be automated but offered as an option with English as default.
Then when opting for English, I log out and back in which indeed reverts E16 to English, except: The installer still is in the former language and stays that way. Humbug now I can't go on with my screenshots for an English instalation manual w.o jumping through some unnecessary hoops.
The installer popups still refer to E17 and E22 as being there as an option, which they obviously are not and on top:
The text(the Dutch one, at least) is too much of an excuse for bugs and mayhem, not very professional ...... we need to remove that and flaunt E16.
In that case it was the pop-up after 10 minutes. Which in my opinion should've been English like the Desktop at that moment.
I remedied the "problem" by cutting internet access on boot. That makes the boot up default to English, as well as the installer.
It mopes a bit about not being able to upgrade the installer but wil carry on anyway. I only needed the English pop-ups for the screenshots.
perfect, bug fixed
it was caused because the menu was a background job waiting for run, with the language conf set to the old value... this fix is not included in 3.7.9 but will be for the next build
the problem wont happen anymore since you can configure the language in each live boot and should work correctly now with the bug fixed
BUT, i suggest you a little tip / trick, by using the boot parameter country=us for example, or there was another to set specifically the language in the boot parameters, it was lang=en or lang=en_US (or "language") if im not wrong