Excerpt from Wikipedia https://en.wikipedia.org/wiki/Zydeco
The origin of the word “zydeco” is uncertain. One theory is that it derives from the French phrase Les haricots ne sont pas salés, which, when spoken in Louisiana French, sounds as [lez‿a.ɾi.ko nə sɔ̃ pa saˈle]. This literally translates as “the snap beans aren’t salty” but idiomatically as “times are hard”, signifying the speaker’s fatigue or lack of energy. The earliest recorded use of the term may have been the country and western musical group called Zydeco Skillet Lickers who recorded the song “It Ain’t Gonna Rain No Mo” in 1929.
Initially, several different spellings of the word existed, including “zarico” and “zodico” (in some dialects of French, r has the same pronunciation used by certain dialects of American English for specific instances of d). In 1960, musicologist Mack McCormick wrote liner notes for a compilation album, A Treasury of Field Recordings, and used the spelling “zydeco”. The word was used in reviews, and McCormick began publicizing it around Houston as a standard spelling. Its use was also accepted by musician Clifton Chenier—who had previously recorded “Zodico Stomp” in 1955—in his recording “Zydeco Sont Pas Salés”, after which Chenier himself claimed credit for devising the word.
In an alternative theory the term derives from the Atakapa people, whose enslaved women were well known for forming marital unions with male African slaves in the early 1700s. The Atakapa word for “dance” is shi (rhymes with “sky”) and their word for “the youths” is ishol. In 1528 Spanish people, the first Europeans to contact the Atakapa, transliterated shi ishol as zy ikol. Four hundred years later, the mixed-blood descendants of Atakapas and Africans would still sway in synchrony to their raucous music, but with a slightly evolved name: zydeco.
Another possible root word for zydeco is as a West African term for “musicking”. Recent studies based on early Louisiana recordings made by Alan and John Lomax suggests that the term, as well as the tradition, may have African origins. The languages of West African tribes affected by the slave trade provide some clues as to the origins of zydeco. In at least a dozen languages from this culture-area of Africa, the phonemes “za”, “re”, and “go” are frequently associated with dancing and/or playing music”