Violettes of these two branches aren't too hard to differentiate, although there are certainly some gray areas. First, what do you know of your family's line? If they go way back to New England or Canada, and there are some French given names, then you should consider digging into the history of the French Canadian (Acadian) family, and an excellent place to start is with www.violettefamily.org - there is a wealth  of information available throught this site.

On the other hand, if your forebearers go back to Virginia, Kentucky, Ohio, Tennesse, or Indiana, and have predominantly English-sounding names (especially, in the earliest generations, names like Edward, John, Thomas, or William) take a look at the genealogical information here. And if your name is spelled Violet or Violett, start here first. Chances are you will find a connection or near-connection somewhere. 

Still not sure? Try posting on www.genforum.genealogy.com - lots of both families contribute, and you will probably get some helpful information. And feel free to contact me directly - I'll give any help I can.