noun
rural dialect; provincial dialect
Refers to the dialect or way of speaking used in the countryside, often with a rustic or old-fashioned connotation.
祖母は田舎言葉で話すので、時々聞き取りにくい。
My grandmother speaks in a rural dialect, so it's sometimes hard to understand.
方言 is a neutral term for any regional dialect, while 田舎言葉 often carries a nuance of being rustic or unsophisticated.
Compound of 田舎 (inaka, 'countryside') and 言葉 (kotoba, 'language, speech').