This came across NPR the other day:
Language Heard During Infancy, Then Lost, Leaves ‘Ghost’ Imprint on the BrainAnecdotally I would agree in some minor way. I grew up in North Central Pennsylvania with a mother from Brooklyn who spoke Yiddish quite fluently, as did her family. I remember hearing a story that she didn't know English when she started school, although I am not sure that would be the case since she was the youngest of three children who, by the time she went to elementary school would have already been in 3rd and 4th grades.
MRI scans revealed that the adoptees showed the same brain activity as native speakers, despite no longer being able to understand and speak anything in the language.
In any case I know my mother and her family were fluent and, when we went to Brooklyn for visits, the language was freely used. I never was taught it or even given any hints about what any of the words meant. I have a hunch that this gave them the leg up on these two young kids with big ears. I do remember the phrasing and style of the words with that unique Brooklyn/Jewish lilt to it. I can still fall into that dialect quite easily. It is almost natural. That's the first bit of anecdotal evidence.
My mom died not long after I turned 13 and contact with the Brooklyn side of the family was lost. No more Yiddish.
When I was in high school I took German, which, as you may know is quite similar to Yiddish- Yiddish being a Germanic language of Eastern Europe that utilizes Hebrew letters. I did okay but never really studied like I should when I got to college. No anecdote here.
But somewhere around 10 years ago I was surfing around the Internet and came across a site that had some talks given by a Hasidic Rabbi in Yiddish. Just for the fun of it I clicked on it knowing I wouldn't know what he was saying, I just wondered. Hence, anecdote 2.
Well, it was clear it wasn't German, but I could have heard it anywhere and would have known it was Yiddish. No mistake. It had the accents and feel of the Yiddish that is buried somewhere in my most early memories. I have a hunch that my brain cells would have been lighting up like a Christmas tree (or Hanukkah candles, might be more appropriate!)
I know this doesn't prove anything. But it was such a deep moment transporting me back over five and a half decades to a time and place long gone.
The human brain is a truly remarkable organ.