drop (one's) aitches

To not pronounce the "h" sound (typically when it appears at the beginning of words), as is done by speakers in some parts of England. She's been dropping her aitches to try to fit in with the other kids.

drop your aitches

fail to pronounce the ‘h’ sound, especially at the beginning of words.

In Britain, dropping your aitches is considered by some to be a sign of a lack of education or of inferior social class.

1903 George Bernard Shaw Man & Superman This man takes more trouble to drop his aitches than ever his father did to pick them up.

ˌdrop your ˈaitches

not pronounce the ‘h’ sound, especially at the beginning of a word, where it is pronounced in standard English

This is a feature of some English accents, for example the London one.