learned or learnt

[Eve]

Work question...

post a project implementation we conduct a review with all parties to see where things could have gone better etc and any lessons we need to take away for future work.

Is it 'Lessons Learned' or ' Lessons Learnt' ??

[monkeymushroom]

I think either is OK and the only difference is that "learnt" is only used in British English.
OED

[nickelrocketgoBooooooom]

either is okay, but learned is better for writing and learnt for speaking.
if you're using informal writing (rather than an essay for example) then learnt is fine there too.
i would use Learned in your case :)

[monkeymushroom]

Or "chiefly" in British English at least.

[VintageRainBoots]

"Learned" (one syllable, verb) is what we American folks use; British seem to use "learnt".

The adjective "learned" (two syllables, pronounced ler-ned) is the same in both British and American English, if I'm not mistaken.