Way past tense

The following verbs have two acceptable forms of the past simple/past participle in both American and British English, however, the irregular form is generally more common in British English (the first form of the two) and the regular form is more common to American English.

Burn
Burnt OR burned

Dream
dreamt OR dreamed

Lean
leant OR leaned

Learn
learnt OR learned

Smell
smelt OR smelled

Spell
spelt OR spelled

Spill
spilt OR spilled

Spoil
spoilt OR spoiled