So far, I was able to start applications in english reliably by specifying the environment variables LANGUAGE (sometimes LANG or LC_ALL) with value en, en_US or C which is also what questions like How to change language of a specific application? explain. env LANGUAGE=en gedit works like a charm.
However, with ubuntu-software I have no luck. Is there any way to start the program in english. I want to write very high-quality instructions in english how to use the software center (including button and other control labels) without switching the system language setup or choosing some other complex approaches like going through the i18n source code.
I'm using Ubuntu 18.10.