Violin is associated with western Classical music where musicians learn by reading printed music and they play exactly what is written, note for note. This music can be extremely complex and challenging. A very accessible example of classical music for the violin would be Tschaikovsky's Concerto for Violin and Orchestra.

When Tschaikovsky wrote it, it was so difficult that no one could play it. The violinist to whom it was dedicated, Leopold Auer, wasn't able to play it, but he taught it to his students, including Jascha Heifitz. Now most serious violinists can play this piece of music, but it remains both challenging and beautiful.

Violin is also associated with Indian Classical music (as in India). They also have a written tradition, although there is more improvisation than is usually found in western Classical. The various fiddle styles have actually preserved aspects of music that Classical lost in the 16th and 17th centuries. Many fiddle tunes are written in scales that Classical no longer uses (Old Joe Clark, Salt Creek, Road to Lisdoonvarna, Swallowtail Jig).

Also fiddle involves a lot more improvisation, which was popular to do during the 1700's but which Classical music lost in the 19th century. Finally, Classical violinists played instruments with a number of different tunings but settled into one tuning (GDAE) by the 1700's. Occasional fiddle tunes and fiddle styles require changing the tuning of the instrument. There are many fiddle traditions, from Scottish to Cajun, from Canadian to Irish, from Old Time to Cape Breton.

Within regions there are multiple styles; for example, Irish fiddling styles vary from county to county. Fiddling is passed down not by written music but through the oral tradition where a younger fiddler learns from an older fiddler directly. Currently fiddlers still learn from each other, either in person or through recordings.

Oral tradition changes music in interesting ways. A fiddler may not exactly remember what someone else played and may play a few notes differently. Also, fiddlers often play for dances and playing the same tune over and over again the exact same way, for ten minutes while people do a whole dance set, is boring. So they tend to vary the tunes.

Also, some traditions are historically related. For example, Devil's Dream was originally an Irish tune which made its way into the Appalachian mountains. Irish and Appalachian versions differ and yet there is still something in common to both versions of any given tune.