Zydeco and Cajun are the premier cultural expressions of the spirited and hardy people of southwest Louisiana. While the two styles have some similarities, they are also quite different. Cajun music as it is known today can be traced back to early Acadian, French, Creole, and Anglo-Saxon folk songs. These early ballads and lullabies - typically concerned with troubles and hard times - were often sung a cappella. For the most part, they were performed at home and passed down orally from generation to generation; however, the singers of these traditional songs were eventually accompanied by simple instrumentation.
Cajun music is, of course, meant for dancing - one-step, two-step, and waltzes. Traditionally, the Cajun dance ("Fais-do-do" in Cajun) was the major social function in Cajun society. The principal instrument in Cajun music is the diatonic accordion, preferably in the key of C. Although it is a German instrument, the Cajun people adopted it in the 1870s. To a lesser degree, the fiddle is also a favorite instrument in Cajun music. Early Cajun bands featured both of these instruments, as well as a triangle to keep the rhythm. Acoustic guitars were added to the lineup by 1920; three decades later, steel, electric guitars, and sometimes drums were added as well. Although Cajun music has changed somewhat over the years and has been influenced by other styles of music - notably country and blues - it has remained a distinctive style. While the music's popularity continued to grow in Louisiana, it didn't enter the spotlight nationally until the mid-'80s, riding on the coattails of the Cajun food explosion.
Compared to Cajun music, zydeco music has a much shorter history. Like Cajun music, the dominant instrument is the accordion, but unlike Cajun music, zydeco adds electric bass, horns, and sometimes keyboards. In a nutshell, zydeco is Creole (black) dance music of southwest Louisiana, blending Cajun music with rhythm & blues and soul. The word "zydeco" is actually a bastardization of an early zydeco song, "L'Haricots Sont Pas Sals" (The Snap Beans Aren't Salted). The first black-French recordings were made in 1928 by Amad Ardoin, an accordion player who played in the Cajun style. However, zydeco didn't begin to evolve - at least on record - until the mid-'50s, when Clifton Chenier and Boozoo Chavis made their initial recordings.
Bob Wills, West Country, Zydeco
The Nashville sound of the 1940s-1950s maybe.
But Bob Wills and the Texas Playboys and other artists in West Country is a completely different sound.
And then there's West Coast Swing, which is really Swing dancing and music in cowboy clothes.
And then there's Zydeco, with those Cajuns. No irish sound there that I can tell, but wailing-priestess-Clannad-crap seems to be what most people think of when they think "Irish" nowadays.
Another part of "Irish" is the drinking hall songs sung by male choruses like by The Clancey Boys. Totally Laurence Welk again, to my ear.