on Just Publishing Advice:
Burned or burnt and learned or learnt are two of a small group of verbs that can end with either ED or T.
Generally, the ED forms are more common in US English, and the T forms are more frequent in British English.
However, in either form of English, you can sometimes make specific choices for the past simple, past participle, or adjective.
Whichever form of English you use, there will be times when you need to decide which variation is correct or simply the best choice.