Being an Australian I am accustomed to -t past tenses like learnt and spelt, so naturally I would write and say "earnt". However, when I wrote "earnt" in an email, Outlook underlined it as a misspelt word.
I did some further research and discovered that in all English dialects "earned" is used instead of "earnt". Why is this the case, and for how long has it been?
As mentioned in a similar question on this site, Wiktionary is the only online dictionary with an entry for "earnt".
NOTE: I checked for this same question on this site, but it only had what I already knew (the validity of the word). I would like to know why "earnt" is not a word.