-ed versus -t

Ben Yagoda (Friend of SbaCL and Not One-Off Britishisms blogger) , who had recently noticed a US journalist saying learnt instead of learned , asked whether I'd covered the ‑ ed/ ‑ t alternation. It's one of those things that I've been putting off for a long time because it would be a very long post. Now I've been shamed out of my laziness. In order to do this in any kind of sensible way, I feel…