I’ve spent a fair amount of time in Michigan because my grandparents live there. By today’s standards, they have very heavy accents, with full Canadian raising and the northern cities vowel shift. They also say ben for been. I understand the first four features but the feature that always perplexed me was that words with a short I sound would become an ee-I sound, similar to how the southerners say pin. So English would become englee-ish to them. This is not the pen-pin merger because they say pen and men with the normal short e sound. Is there a name for this phenomenon and if there is, how did it come about?