Birdsong

Messiaen had a life-long interest in birdsong: he was an expert amateur ornithologist and used this knowledge in his composition. Messiaen was not the first composer to try to represent birdsong in pianistic terms, and there are well-known examples that pre-date Messiaen by many years such as Liszt's second Legend - 'St Francis of Assisi preaching to the birds.' However, Messiaen's approach is different in that his quest for accuracy is far greater since he wants to produce a true recreation of nature rather than merely hinting at it. Messiaen's style of birdsong writing developed throughout his career, demonstrated by comparing an earlier use of birdsong in 'Regard des Hauteurs' - the eighth of Vingt regards sur l'Enfant-Jésus - with any of the pieces from Catalogue d'oiseaux (1956-8).

Hindu rhythms

In Technique de mon langage musical, Messiaen explains that the thirteenth-century Hindu theorist Carngadeva produced a table of 120 deçi-tâlas that was reproduced in the Encyclopédie de la musique et dictionnaire du conservatoire, (edited by Lavignac and La Laurencie and published in Paris between 1913 and 1931 [Part 1, Volume 1, pp 301 ff]). Messiaen did not carry out any extensive research into Indian music in general, but was fascinated nevertheless by these, and their possibilities. They became one of the fundamentals of his musical language and he made extensive use of them in all aspects of his music.

Greek metres

Messiaen's interest in Greek metres began during his student years at the Conservatoire. His music history teacher during this period, Maurice Emmanuel, had an extensive knowledge of Greek metres and wrote an article on the subject in the Encyclopédie de la musique et dictionnaire du conservatoire; as with the Hindu rhythms, this book was Messiaen's prime source on the subject. The bases of these metres are the two values which combine to each make one:

The long, which is represented by a horizontal line:

The short, which is represented by a U-shaped symbol: U

Rhythmic augmentation and diminution

The augmentation and diminution of rhythms are procedures used by Messiaen to vary and add interest to rhythms and thus make them less predictable. In Technique de mon langage musical, Messiaen states that J. S. Bach used these methods, although in the simplest ways. The following shows how simple augmentation works:

A has the value of 5 semiquavers
B has the value of 5 quavers
C has the value of 5 crotchets

Therefore, B is an augmentation of A, and C is a varied double augmentation of A. The following demonstrates how augmentation through the addition of a dot to a note works:

Simple diminution and diminution by withdrawal of the dot work in the opposite way to the above examples.

Personnages rythmiques

The concept of personnages rythmiques is derived from Stravinsky's The Rite of Spring. Each personnage is a short rhythmic cell that has certain constituent elements, which include mobility and immobility, and for which their juxtaposition is the basic idea. Although a mobile cell is one that can either increase or decrease in value, immobile cells always remain constant. Messiaen noticed how Stravinsky manipulates rhythmic cells in The Rite of Spring (particularly in the 'Sacrificial Dance', which is the most complex section), and compared the various cells to theatrical characters. In his analogy, Messiaen compares a cell which increases in value to a character who dominates the scene (the one who does the acting), the cell which decreases to a character who is acted upon, and the immobile cell to a motionless character who observes the scene. This led to Messiaen giving the technique the name personnages rythmiques. Although in Vingt regards there is no clear example of this technique, its influence can be seen throughout, in passages that contain at least two rhythmic cells, where one increases while the other decreases. One example occurs in 'Par Lui tout a été fait'. In Vingt regards, Messiaen employed Stravinsky's initial concept; however, later works, such as the Turangalîla-Symphonie, employ a more developed approach. For this reason alone, personnages rythmiques must be considered a vital part of Messiaen's musical language.

Conclusion

These techniques take on an overall cohesion when their relationships are examined. In many instances a technique can be applied both harmonically and rhythmically (or vertically and horizontally), producing paired relationships. They are as follows:

1. Modes of limited transposition and Non-retrogradable rhythms are built on symmetrical patterns. According to Messiaen: 'The modes of limited transposition realise in the vertical direction (transposition) what non-retrogradable rhythms realise in the horizontal direction (retrogradation)' (1944, 62).
2. Added values are the rhythmic equivalent of the harmonic added notes.
3. Asymmetric augmentation is the harmonic (and vertical) equivalent of the rhythmic (and horizontal) Personnages rythmiques, to which can be added the relationship between polyrhythms (the superposition of rhythms) and polymodality (the superposition of modes). These types of relationship are called by Messiaen the 'Charm of Impossibilities'.
4. Non-retrogradable rhythms can also be applied to the area of form, resulting in a non-retrogradable structure.
5. Rhythmic augmentation and diminution form a pairing, as do Rhythmic canons and Rhythmic pedals, which are based on the same principle.

This collection of techniques contains a number which were used by previous composers; some are adaptations and the rest are entirely of Messiaen's own invention. Nevertheless, they provided him with a comprehensive, contemporary compositional system.