I never thought I would fall into the Carter obituary vortex, but here I am.
I find this video so interesting. Alisa Weilerstein, who is quite young, has the kind of guarded "grown up" affectation (and diction) that I often observe in successful string players in their 20s and 30s (perhaps she was nervous). Elliott Carter, who is quite old (103 in this video) actually seems young and free in comparison.
He is so physically IN the music when he talks about it. The way he speaks is never guarded. It is expressive and honest, both when he is talking with Alisa, and when he is coaching her.