I don't think I can rule out the water or gravitational fields, or just something about the architecture that does things to a child... but more seriously. I have a theory about what's really going on.
The toddlers are picking up the NYC accent from their parents who "don't have one" --because we are talking about people who have lived in the city for a decade or more.
The real question is WHY do parents notice it when their child says it.
"over here" is a phrase they *really* notice.
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