Is it learned or learnt?

These are from a set of words which has two forms of the past.

These include the following:
burned/burnt
learned/learnt
smelled/smelt
spelled/spelt
spilled/spilt
spoiled/spoilt

Usually, when forming the past tense of a verb, the -ed form is used, while the -t form is used mainly for adjectives, but not always.

Examples:

  • What have you learned? [perfect tense]
  • It was burnt toast. [adjective]

NB: Archaic English uses the exception (but this is pronounced differently) – ‘a learned man’.