Having multiple TLDs is not mutually exclusive with putting the browser language list first. Not every browser has always supported the language list (certainly not when the google.tld names were originally registered) and the TLD can serve to do more than change the default language.
> which in turn support different languages.
They'll default to a different language for the region in absence of any other setting (language list, account preference, browser cookies) but it's not the function of the TLD to override this when the information is present.
> My preferred language is always English but Google normally redirects me to “Google Argentina” (.com.ar, in Spanish by default) from the .com based on my IP and I have to fight it to switch back to English.
Redirection to a different TLD is based off geo-ip not your language setting and done for more reasons than just to serve you a specific language in absence of other language info. You're really fighting Google thinking you (or possibly your account) is coming from Argentina and your browser possibly not sending a language list (or a fake one). I had to correct something similar once where the IP block I had been coming out of had previously been in use somewhere in Asia, I just gave updated info to this form https://support.google.com/websearch/workflow/9308722?hl=en and it was updated and stopped redirecting me. Of course if you actually are coming from Argentina then they won't update it.
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Rather than a bunch of talk though here is an actual demo of what I get browsing to google.com.ar using English in the browser UI but with with German set as my preferred language in the language list: https://i.imgur.com/N3XOSvg.png clearly .com.ar didn't default to serving the page in German on its own nor was there any history in the browser so the language list the browser sends is preferred over the TLD you load. I'd double check you don't have a privacy setting or extension stripping this info.
Having multiple TLDs is not mutually exclusive with putting the browser language list first. Not every browser has always supported the language list (certainly not when the google.tld names were originally registered) and the TLD can serve to do more than change the default language.
> which in turn support different languages.
They'll default to a different language for the region in absence of any other setting (language list, account preference, browser cookies) but it's not the function of the TLD to override this when the information is present.
> My preferred language is always English but Google normally redirects me to “Google Argentina” (.com.ar, in Spanish by default) from the .com based on my IP and I have to fight it to switch back to English.
Redirection to a different TLD is based off geo-ip not your language setting and done for more reasons than just to serve you a specific language in absence of other language info. You're really fighting Google thinking you (or possibly your account) is coming from Argentina and your browser possibly not sending a language list (or a fake one). I had to correct something similar once where the IP block I had been coming out of had previously been in use somewhere in Asia, I just gave updated info to this form https://support.google.com/websearch/workflow/9308722?hl=en and it was updated and stopped redirecting me. Of course if you actually are coming from Argentina then they won't update it.
.
Rather than a bunch of talk though here is an actual demo of what I get browsing to google.com.ar using English in the browser UI but with with German set as my preferred language in the language list: https://i.imgur.com/N3XOSvg.png clearly .com.ar didn't default to serving the page in German on its own nor was there any history in the browser so the language list the browser sends is preferred over the TLD you load. I'd double check you don't have a privacy setting or extension stripping this info.