Celtic Music 

The term “Celtic music” does not refer to an actual genre of music; instead it expresses a world view.  It is today used to express a genre of music that is easy listening mood music.  It is non specific to any Celtic cultures such as Irish, Scottish or British.  It is today used by artists and recording studies to describe a genre of music that evolved out of the folk music of the Celts of Western Europe.

Celtic music can take on two meanings.  The first can be accorded to the music of people who call themselves Celts.  Secondly Celtic music can refer to qualities that are unique to the music of Celtic Nations.  

However, Celtic music is usually applied to Irish and Scottish Celts.  Each has produced distinctive styles of music, yet traditional Irish or Scottish Celts themselves prefer to avoid the term Celtic Music.  Definition of Celtic music has been further compromised with the advent of Ireland promoting it as a product of Ireland.  Truth be told, both Irish and Scottish people share Celtic ancestry and as a result have a common musical heritage.

Celtic music is particularly popular in areas such as the USA, Wales, Cornwall, the Isle of Man, Brittany, Spain and Portugal.  Yet is perhaps strongest in Brittany and Wales where they hold annual festivals and eisteddfods where this music is the theme.

Little is known about the roots of Celtic music
The Celts did not possess the written word and instead handed down their traditional beliefs and culture practices through symbols and the spoken word in the form of folklore.  This holds true to music too.  While Celtic music is today very visible, its roots are very ancient.  It is purported that Celtic music dates back almost 3,000 years.  The only reason that it exists today is because the Celtic civilization has continued without break since then.  The oldest unbroken traditions are relevant in Welsh and Irish Celts.

Throughout time Celtic culture has evolved in keeping with the times.  For instance ancient Celtic traditions were adapted by and transformed by the Druids.  In turn their traditions were transformed by the Romans and then by the Celtic church in the form of Christianity.  The continuation although evolved, continued to keep the Celtic essence although in a new form.

Six Celtic nationalities have been identified and then divided into two groups in keeping with their linguistic tradition.  The Q nationalities are known as Irish, Scottish and Manx while the P Celtic traditions are relevant to Cornish, Breton and Welsh Celts.

The two groups are differentiated by the range octaves relevant to each group.  The Q group have an extended range at time of more than two octaves while the P group are reduced to a half octave.  
However there is a lack of thread between the groups which are able to unite them. So this means that musical styles of the ancient Celts and the original sound of their music is today a complete mystery.  

The living legends of music are highly varied and the music between Irish, Scottish and Brittany regions differs as a result.  Wales, Cornwall and the Isle of Man have undergone recent revivals but the area of Galicia left no Celtic language and with it no legend.  Even though Galician music claims to be Celtic the language itself descended from Galician Portuguese.

Common characteristics
It is not easy identifying the characteristics common to Celtic music.  What we today understand as Celtic music was once common to Western Europe.   Forms such as jigs for instance are thought to have derived from the baroque era while polkas are said to have Czech or Polish origins.  

That being said, there are some genres specific to Celtic countries.  Their specifics are based on song traditions and specific language characteristics.  For instance Highland Scotland lays claim to the Strathspeys which mimic the rhythms of Gaelic languages from Scotland.  

Modern revival
There is one person who is said to have saved Celtic music from perhaps extinction.  Francis O’Neill.  This man collected over 3,500 Celtic tunes dating back thousands of years and made them available to musicians around the world.  Nothing was written down and while he played them a friend who read music was able to transcribe them for future generations.