Errors, and transformations, are inevitable in an oral tradition because of a number of factors. Firstly, there are limits to memory and this will introduce variation, particularly when a tune is first learned. Additionally, melodies will be misheard when learned aurally and "wrong" notes substituted, again especially when a melody or song is unfamiliar and/or complex. The best of these "errors" are taken up by the community of performers, either locally or more widely, which is how the tradition evolves.

Another source of variation arises directly from folk culture which values improvisation and the role of the individual performer in creating an individual and unique version of a song or tune. This is a more conscious and controlled source of variation than that outlined above. Here, the "bare" version of the tune or song is related to as a vehicle for development and the expression of one's personal skill and temperament. In carrying out this improvisation, there are certain "rules of transformation" which the folk performer can use to modify the tune. For example, folk tunes or melodies usually stay in the same key. Folk tunes generally do not undergo a process of development and modulation familiar in post-baroque classical music or jazz, therefore notes within the same key give a basis for modification. This is one type of "rule of transformation".

To say more about the above, folk music and early music commonly use modal scales on which to base their melodies and harmonies. Modal scales generally rule out the power of the dominant note, which is of enormous importance in much of western music. In tonal western music, the tonic note and the triad chord constructed from it plays the most important role, and the tonic is the usual starting and ending note of any piece of music. The second most important note is the dominant, the fifth note of a scale, and the triad chord built on it. Most modal scales do not have a semitone between the seventh and eighth note of the scale, and this means that the fifth note of the scale does not possess the yearning quality, the need for a resolution to the tonic note, that occurs in the case of more conventional scales.
Additional rules are seen in the rules for ornamenting melodies, which give choices of the type of ornamentation, where the ornamentation is used in the tune, and the rythmic and dynamic impact of the ornamentation. Such rules of transformation vary from region to region and performer to performer, and there are also differing conventions between different types of tune, slurs across strings being more common in hornpipes than in jigs, for example. In songs, the primary prpose of ornamentation may be to highlight the meaning of the words or the emotion underlying the words, whereas in a tune played by an instrument, the purpose of ornamentation may be to highlight a rythm or to fill a space in an interesting way, or to add a distinct voice to the melody.

The performing arts that have no lyrics(a string quartet, a celtic jig, a ballet, a symphony, a painting) can be understood primarily on an empathic and emotional level, however,written works such as literature are on the opposite end of the spectrum because they are able to convey meaning only by their recourse to language. It should be noted, however, that the performing arts do have their own symbols for choreography and dance, notation for music, etc., and that these function like language to their performers. Science similarly has its own notation systems which function like a language for scientists. And,finally, people have their own ways of expressing emotion, ways which are considered by some as language-like.

Fiddle Traditions of Northumberland

In the mid-nineteenth century, the fiddle was the most popular traditional instrument in rural areas of Northumberland. The fiddle was an important part of many ceremonies and traditions, such as weddings, markets and fairs and it was used as an accompaniment to song and dance at many social gatherings.

The most popular tunes were jigs, reels and hornpipes, in common with most parts of England and Ireland. However, there is a distinctive Northumbrian tradition of playing these tunes, exemplified particularly by the style of playing the hornpipe. The Newcastle style is examined in the fiddle tutors of W.C. Honeyman, published at the end of the nineteenth century. This involves a type of "back bowing", and as Honeyman explains it, " the student must play with the upper third of the bow only; playing the leading notes, immediately before the bar, with an inversion of the rules of bowing - that is, with a strongly accented down bow. The first note in the bar is then played with an up bow, the short note after it being then crisply caught with a quick down stroke. It must be played vigorously and with great spirit. No written description can convey any idea of the neat sprightliness of this style of bowing".

The earliest hornpipes were in 3/2 time and these gave way over time to the hornpipe in 4/4 time. Hornpipes tend to be tunes played at a middle speed, perhaps depending on the dance it is accompanying, with a lilting, bouncy feel. The tunes are syncopated and have "swing", the dotted notes of musical notation attempting to convey something of the feel of the music.

Northumbrian music tends towards a style that is quite distinctive amongst the traditional musics of England and Scotland, and it has been felt that these peculiarities arise from the influence of the Northumbrian smallpipes, which have unique playing qualities. It is characteristic of Northumberland tunes, for example, to have octave leaps, deriving from the ease with which octave jumps can be obtained on the pipes.