Learn (irregular verb)

'To learn' is an irregular verb. Its forms are given here:

Base form	past tense	-ed participle	Remarks
learn	learned or learnt	learned or learnt	The variation between 'learnt' and 'learned' is a regular variant learnt is less common in American English. See note [b] in category:Quirk class 1 A

This is one of the "the 250 or so irregular verbs" listed in Quirk 1985. The list "contains most of the irregular verbs in present-day English ... but is not meant to be exhaustive, particularly with regard to derivative verbs." AWE has copied most of the entries in that list. The verb 'to learn' belongs to Quirk's Class 1 A

You may also want to see Learned - learnt for more on the variant, and Learn - teach for a point on usage and meaning.