(Problem with a Spanish computer system is that spellcheck doesn't work in English,
Rob, you should be able to download extra dictionaries... I can swap between French (which I need) and English (which I'd like to think I don't, but as time goes on...) with a right-click in the text box. That's with Chrome. Same with Libre Office, where I can specify at each line which language it should work in (important also for spacing rules, quotation marks etc).
The worst experience is MS Outlook, which insists on guessing, usually gets it wrong for a few lines and then highlights the errors it created by "correcting" one language to another... I'm obliged to use it at work, unfortunately.