I bet this is Colline (Hill) by Jean Giono (1929).
The story is set in Provence (southern France), next to the mountain of Lure, in a very small village called "Bastides Blanches". Giono was born in Manosque (Provence) and spent most of this life there, about 40km from the mountain of Lure.
As for the story, an old man warns others against nature taking revenge against humans. Characters start to freak out about it, and discuss a black cat appearing before disasters occur (earthquakes, lighting striking people, etc.). Then, several bad events indeed happen: water shortage in the village, a small girl getting sick, a fire spreading to the village...
In addition, the story features a "village idiot" called Gagou, who is the lover of Ulalie. Ulalie is depicted as a ugly, but strong, independent woman.
As you mention the word "déparler" (translated as "raving" in the 2016 translation in English by Paul Eprile), the novel includes a few occurrences of it, in particular one character uses it to describe the old man who is dying.
Finally, there was a TV movie adaptation of the novel in 1980.