Now that you mention it, we did Latin roots, too, in the mixed grade school I attended after the school with pull-out enrichment. It was for the top group in each two-grade cluster, and went by morphographic spelling. Might have been a similar model, because that school also had semi-independent programming. I entered the 4th/5th cluster midway through 3rd, and then the 5th/6th cluster the next year. And then my parents moved me elsewhere, so I never did reach the point where there were no children older than I. It wasn't technically a GT program, though, probably more like a version of differentiated instruction.

...pronounced like the long vowel and first letter of the alphabet...