I don’t understand why avast mixes the languages.

If I use avast in English, then I want all pup ups and GUI in English, no matter where I am or the language of my OS.

The only valid reason for avast to take into account any other language is for specific area offers or specific area support. Only for those matters, avast could potentially consider my OS settings (or my IP), so to offer some upgrade in my currency or according to my location for example (and even then, some users won’t like it either).

Ideally, if I live, say, in Japan but my avast GUI is in English, then avast could offer me to upgrade using Japan’s currency (or offer me free phone suppert for Japan, just as an example), while the pup ups and information should still be presented in English (as my avast GUI).

My area code, my OS’s language and Avast’s language are not necessarily the same as Avast’s Developers (and marketting guys) are assuming.

Avast Software, please follow what the users are setting in Avast GUI, without assumptions or mix ups.