Years ago I used to make fun of my mom, who is of French-Canadian descent tho she was born and lived in New Hampshire, when she would pronounce words like “calm” & “palm” as “carm” & “parm”. Well, when I went to my grandmother’s funeral a few weeks back, I met her sister (my aunt) for the first time in about 8 years, and the aunt also said “carm”. Is there some odd facet of the French language which would account for this oddity?
I’ve lived in New England my entire life and have never heard anyone do this. Maybe you’re mom’s family is just weird, huh? 
In New England, it’s much more common to drop the “r” – “cah” for “car”
My graduate English professor said that US English is divided into “r-less” or “r-ful” dialects (the official term is “non-rhotic” and “rhotic,” but this is a guy who created his on phonetic transcription because he didn’t like the IPA version). Ask people to say the word “murderer” and you can figure out which one it is.
True. But when Norm Abrams builds a chest of draws, he makes sure the draws will fit by checking the drawering.
drawer => draw, but drawing => drawering
There’s a hamlet in Northern New York, between Massena and Potsdam, called Norfolk – or rather, written Norfolk, pronounced “Norfork.”
Other than that, I got nothin’ – and a couple of branches of my family were, separately, of French Canadian, and northern New England ancestry, so it probably would have shown up if it were widespread.