Here's a sample of my favorite Tejano singer Pete Astudillo. He really mixes it up with all types of music. This one has the classic cumbia beat with the accordian in the background. Man...I have to figure out how to post audio files. I think Tejano music is amazing. Sometimes it sounds German, sometimes it sounds Spanish, and sometimes it's almost Arabic. I think it is one of the most romantic genre of music out there. All songs in Tejano music require you to dance close to your partner, or at least hold them in an intimate way.
I'm not sure about the Spanish, but I do know the French have probably been assimilated somewhat...I think after they lifted themselves up out of the fetal position they took on the accordian.