Patois
Definition: non-standard speech, such as a regional dialect
It’s French, pronounced “PAT-twah.”
There’s a blurry line between what is a patois and what is an entirely different language. A common example is Jamaican English – is this a regional dialect, or a form of creole?
Also murky is where the line sits between a “accent” and a “dialect” or patois. This page offers one explanation:
An accent refers to how people pronounce words, whereas a dialect is all-encompassing. A dialect includes the pronunciations, grammar and vocabulary that people use within a group.
So, a dialect or patois is more than an accent – it includes a rearrangement or invention of parts of speech that goes beyond pronunciation.
Also on that page is this humorous quote from a Yiddish scholar:
A language is a dialect with an army and a navy.
The implication is that countries define languages – something is a “language” if a government formally says it is.
Why I Looked It Up
I remember when Chet Hanks (son of Tom Hanks) used a Jamaican patois during an interview and caused a uproar about cultural appropriation (also, it was just weird). That was the first time I had heard the term.
Then, in the H.P. Lovecraft short story, The Shadow Over Innsmouth:
[…] they passed on across the moonlit space with varying their course – meanwhile croaking and jabbering in some hateful guttural patois I could not identify.
Postscript
Added on
From Spycraft for Thriller Writers:
FBI patois includes adding “Bu” as a prefix to common words.
In this case, it refers to a professional dialect, not a regional or ethnic dialect.