Is Yesterday about Paul's mother?

Paul & Mary McCartney

Paul McCartney has recently suggested a ‘subconscious’ inspiration for the line I said something wrong/Now I long for yesterday was his regret at once chiding his mother for ‘talking posh’:

“Sometimes it’s only in retrospect you can appreciate it. I remember very clearly one day feeling very embarrassed because I embarrassed my mum…We were out in the backyard and … she would talk what we thought was a little bit posh. She said something like ‘Paul, will you ask him if he’s going … I went ‘Arsk! Arsk! It’s ask mum.’ And she got a little bit embarrassed. I remember later thinking ‘God, I wish I’d never said that’

Paul lost his mother when he was fifteen to a cancer that had been kept secret from him. The social convention of the time meant that he was expected to move on swiftly from this trauma. This had a profound and incalculable effect on his life and his art. 

One of these reverberations was a strengthening of his bond with John, who also experienced teenage bereavement.  It may also have been a submerged influence on Yesterday.

In its lyrical structure, however, Yesterday is clearly a conventional, if enigmatic, song about lost romantic love. The line why she had to go, I don’t know, she wouldn’t say can be taken literally — though it perhaps alludes to the squabbling lovers in We Can Work It Out. 

The first person narration less autobiographical than what John would later call ‘one of Paul’s story songs’. This was a highlighted a key difference in their songwriting approach, particularly post the first two albums. John put an increasing emphasis on expressing his personal emotions (‘the thing I know most about is me’) while Paul largely kept to the standard songwriting convention of aiming for universality.

At school, in the English classes he enjoyed, Paul would have been asked to write stories to match a title in a specified genre. Here the brief was similar but with the approach established by the melody.