Georgian folk songs are distinguished for the variety of types among which we find the forms of homophonic, polyphonic and synthesized structure.
The diversity of Georgian polyphony is a result of the interaction of several compositional principles by different versions. This process is also facilitated by the functional differentiation of performers – traditionally, two soloists in upper voices (I and II voices) and a bass (more often performed by several performers). The kind of polyphony usually depends on the principle of consonance between choral bass and upper voices (ostinato, drone-continuum, recitative drone and melodic formulas), and on the principles of movement and coordination of the two upper voices (parallelism, free-contrasting voice movement, vocal responses, indirect voice movement – a drone of a short duration in any of the parts). Krimanchuli – a specific upper voice yodel-type ostinato, and gamqivani, which has less ostinato also play important role in the formation of the original structure of polyphony in Western Georgia
The types of Georgian traditional polyphony are created by five compositional principles:
Drone principle – movement of the upper voices over a bass drone (homophonic structure);
Ostinato principle – movement of the upper voices over a bass with ostinato (repeated) formula and overall ostinato movement in all voices;
Parallel principle – parallel movement of voices;
Complex (synchronous) principle – synchronized movement of chord complexes;
Free contrasting principle – unlimited independent voice movement (polyphonic structure).
Two or three of these principles may be realized simultaneously in one song, creating synthesized types of polyphony. This can be, for example, homophonic structure with elements of polyphony (the majority of three-voiced drone-based polyphony), or polyphonic structure (three-voiced singing with krimanchuli and four-voiced work songs).
Combination of the principle of synchronism with other principles is especially frequent: with drone (forming recitative bass drone), with ostinato (the above-mentioned overall ostinato) and with the principle of parallelism, which naturally comprises the principle of synchronism.
The synthesized form is mainly found in drone-based three-voiced songs (more often in Eastern Georgia). Here the drone principle is combined with the principles of parallelism realized in upper voices and free-contrasting voice movement (the latter is found less frequently).
The synthesized form is mainly found in four-voiced song from Guria, Achara and Imereti. It includes upper voice ostinato (krimanchuli), recitative second voice, episodic high bass drone, and a melodically developed low bass (fourth voice).
The single homophonic multi-voiced singing is less common in drone-based form (found mainly in two-voiced songs), ostinato (the perkhuli, dance songs, work songs) and especially parallelism. All Georgian singing is characterized by synchronous polyphony (chord structure) and free-contrasting pure-form voice movement (polyphonic structure).
Georgian church hymns are distinguished from secular songs for more homogeneity of polyphonic forms. The eastern and western modes of hymns are based on compositional principles of synchronism and partially on parallelism. Of the embellished (gamshvenebuli) modes, Karbelaant Kilo is distinguished by a melodically developed middle voice and parallelism in the marginal parts; unlimited independent voice movement with parallelism is common to the Shemokmedi and Gelati schools of chant.