I can second HighJinx... DH is from Cornwall and seems to slip back into weird speech when speaking to the DCs in a kind of enthusiastically impressed way, e.g. 'Daddy, earlier we were making strawberry rabbit jelly' 'Was you my darlin'?'
I stand there with my SE England accent and correct him, saying stiffly 'Don't use bad grammar in front of the children, darling.'
DH did actually read this over my shoulder and his response was 'I don't think it's an inability to conjugate a verb, so much, just dialect...' He also didn't realise that he did that!