That accent is not yet gone up here, but it is much less common. He sounds about like my grandfather. Gramps had him for freshman English at Pinkerton Academy in 1910, and didn't think much of him. This is not surprising. Frost had moved back to take care of his mother's farm and wasn't happy about it. He took the teaching job for the cash money, but 9th-grade boys are no treat. He liked teaching college in Vermont better.
I read this to my granddaughters a few times a year.