'patois' is both the singular and the plural form; the singular form is pronounced /pætwɑ:/ and the plural form is pronounced /pætwɑ:z/.
1.
A patois is a form of a language, especially French, that is spoken in a particular area of a country.
In France patois was spoken in rural, less developed regions.
= dialect
N-VAR
2.
A patois is a language that has developed from a mixture of other languages.
A substantial proportion of the population speak a French-based patois.
= creole
N-VAR