Language, country and formats
Two settings, and they are not the same one.
Lyncera's interface speaks twelve languages, and your choice applies everywhere — the web app, the extension panel, and the language a message draft is written in.
Your country is a separate setting and changes only formatting: how dates, times, numbers and currencies are written, which day the week starts on, and the hours in the calendar gutter. A Finn working in the United States can read Finnish and still see American dates.
Both live in Settings → Profile. Reading a LinkedIn profile is different again: the panel reads a page in the language of the person on it, which is why a Spanish profile parses correctly whatever your interface says.