Maybe an odd way for it to stick, but "barn" makes me think of the Scots word "bairn", which also means "child." They could possibly have the same roots/etymology, come to think of it.
Many parts of the British Isles were under Danish control from the 9th to 11th centuries. Even English still uses some words left over from that time period.
Does "barn" have two syllables?
She sure makes it sound like it.
No, only one.