AIBU to expect educational professionals to use correct grammar when talking to children?

[nofunanymore]

Everytime I hear a childminder, teacher or teaching assistant in a professional context using phrases like 'I seen it' or 'I done it', it totally grates on me. Is it the inevitable march of language, or am I justified in my annoyance?

now pedants- pull apart whether I should have written "an MSc" instead of "a MSc"

I am a CM and a TA and I speak proper to the children. Thank you

An.