Danny's Dead and Who's Got the Will? - S4-E12
Continuity mistake: At the start, when Fran joins Niles, she's holding a green mug in her left hand and a muffin in her right hand. But the mug and muffin suddenly switch hands when Fran and Niles head to the sofa.
Answer: Children's brains and language skills are still developing at that age and they adapt to the environment they live in. My former boss was born in England and moved to the US at about eight years old. She completely lost her British accent by her teens, even though her parents still spoke as typical English citizens. A Japanese co-worker and his wife, also Japanese, spoke English as their second language. Their two children learned both English and Japanese simultaneously while growing up and spoke each language with the appropriate accent.
raywest ★