alerts: default voice/language

I think the default language should be English, but it seems it is the first available:


Maybe when the browser language is not English, we could raise a pop up asking if it should change to the browser language

Start by locating the alert language selection and the logic that chooses the first available language in the TypeScript/Vue frontend. Check how the browser language is exposed, then define behavior for English defaults and non-English browser languages, including whether a prompt is shown. Done means the selected default and prompt behavior are covered and alerts use the expected language.

Written by the indexing model from the issue text.