Imagine SP and I discussing the letters on my shirt, as we often seem to these days. On this occasion, the 'A' in '
I gently correct. "A is for aeroplane."
He usually knows this one. I try again. "A is for apple. A is for ant."
SP remains adamant. "A. Up."
I try a different tack. "U is for up."
A pause, and a confused little face.