Jèrriais is a language spoken on Jersey (Jèrri), one of the Channel Islands, particular in the parish of St. Ouen. According to the 2011 census, there are 1,700 speakers. Jèrriais is one of the langues d'oïl and is related to Norman, Dgèrnésiais, Picard, Gallo and Walloon. It has been spoken on Jersey for over 1,000 years and has been influenced by Celtic, Norse and Frankish languages.
For many centuries the official written language of Jersey was standard French, while the people spoke Jèrriais. In 1912 compulsory education was introduced in Jersey and English replaced Jèrriais as the medium of instruction. After this, children were forbidden from speaking Jèrriais in school.
source
wikipedia.org,
omniglot.com &
ethnologue.com