About 1000 BC. Celtic people settled in northwest Spain. The Celtic culture and society established many musical traditions. Most commonly used are the gaita (bagpipes), drums, flutes, clarinet, and harps.
Also along the northern region of Spain there are the Basques. Basque music uses a lot of vocals, specifically choir-singing, in their music. They have some unique musical instruments: the Txalaparta (a wooden instrument played with sticks), and the Txistu (a one-handed shepherd's flute), and the Alboka (a horn-clarinet). They also use various trumpets and drums.
From the northeastern part of Spain we get the Jota-music style. It has spread over all of Spain and has a relatively up-beat, rhythmic style, characterized by repeating patterns and tonality. Castanets, flutes, tambourines and other instruments (like the guitarro) are used along with vocals. In other parts of Spain the Jota style changes. Sometimes it has a slower beat.
The Flamenco was born in Andalusia (southern Spain), and is known worldwide by its exotic personality. As it spread to the other Andalusian provinces each added to it. The blend that stuck is mostly from the nomadic gypsies influence, however, some might claim that the Moors introduction of a guitar-like instrument ('al Khitara') is just as significant, as today, the guitar is very important in the Flamenco. The strings of the guitar are played one at a time - plucked interchangeably. The dance, drums, and hand-clapping, are a part of the modern Flamenco as well.
Other styles that are well-known for their music and dance styles are: Bolero, Fandango, Muñeira, Paso Doble, Sardana, Sevillanas, and the Zambra.
Popular Music of Today
The influences of traditional music can definitely be seen today, especially in the rising popularity of Celtic music. And now the influence of modern music has brought rock, hip-hop, and rap into the mix.
Links to Official Sites of Spanish Speaking Musicians and Singers