For whatever reason Blizzard tries to guess location of the user based on the browser’s language preferences (while many other sites try to guess users preferred language by their location).
If you set en-gb (british english) as your preferred language in your browser it should direct automatically to en-gb site. In Firefox this is done by opening Options -> Browse down until Language, click “Choose” button next to “Choose your preferred language for displaying pages” and move en-gb to top. Add it if it’s not present.
Note that it can also affect sites which use the feature properly (not that many) so some sites might default to English instead of eg. your local language.
In Chrome language settings, is the US one still there available? If so, maybe try removing it so that only Slovak remains? Maybe add English (UK) as a second language option.
Not come across this issue yet so forgive me if I am talking out of my rear end
Language of the browser does not directly matter. It’s the language preference for the web sites which matter, though if you install eg. Slovak language browser it might by default include the Slovak language in your language preferences. I personally have Firefox UI in English but my language preferences for web sites also include my local language along with English.
In my earlier reply I already described the process to change the language preference for the web sites in Firefox. Similar option should be present in the other browsers, too. I don’t personally use Chrome so I can’t exactly tell where such preferences are. From what I remember you can add multiple languages and order them in chrome://settings/languages with each language having option to make it also the UI language and optional translation target. For this issue the English (UK) should be higher than English (US) or plain English.
Whole protocol level language negatition was in theory good idea but in practice it never really worked that well so most sites (for a reason) don’t use it. Especially to determine regions…
My country is Finland, but we study English by default atleast from teenage.
I did my gindergarden in english version tho
But anyway, i prefer my english accent more into US than UK, UK ENGLISH is more robotic version, my opinion anyways, US ENGLISH is more flexible and easier.