So much of the story in the detail

In the General Instruction of the Missal in paragraph 135 'reader' is spelled with a lower case 'r' but 'priest' is spelled with an upper case 'p'. Why?

'Homily' is with upper case 'h' but 'cantor' with lower case 'c'.

And 'faithful' with lower case 'f'

It reminds one of the Cork joke about the woman walking along the Lee, who shouts out; "help, help, my son the engineer is drowning".

As silly as that.

There is a story behind everything.