Can I split my account by language?
I would like to transfer one of my languages to a different email address without losing my streak or my fluency. What happened was my son was learning one language and I started learning another. I don't want to lose my stats by starting over.
Sadly, no. But you can start a new account and test out of what you do know to regain the same level.
It would be a pity to lose your progress, but to be fair, level 7 (or 8, I don't know which one you are learning) can be regained pretty quickly, especially if, as others already have suggested, you do a placement test.
Normally, If Duolingo's statistics are correct, when you do the placement test that you have the choice to do in the beginning, it should get you to the same lesson, or the one after or before. Once I did the placement test with another account and it only brought one lesson before the one I was at. First you should do the test and if it gets you approximately to the same lesson than delete the language that you're learning on your old account and restart with this one, but your streaks however will be lost with your lingots.