What chord progressions are used in traditional Celtic music?

Question

What chord progressions are most often used in traditional Celtic music, such as aires, jigs, and reels?

For example, harmonies in classical music are dictated by the common practice rules and focus a lot on the dominant chord and voice leading. Blues and jazz use the twelve-bar blues and its variations and often use the progression ii-V-I. Jazz also uses more complex progressions like the Coltrane changes and modal chords. What's an analogous description of the chord progressions typically used in Celtic music?

Answer 1

There are many English folk songs and Celtic tunes and airs that use the Dorian Mode, Mixolydian Mode, and the Aeolian Mode (the Aeolian is perhaps not as exotic as the other two, so maybe these don't stick out as much).

Dorian tunes include The Swallowtail Jig, Road To Lisdoonvarna, Scarborough Fair, All Things Are Quite Silent (which also has a B Part that leans very heavily into Mixolydian), What Shall We Do With The Drunken Sailor, and many more. To modern ears, used to chord progressions, the signature chord sequence would be minor i - IV, and as with all of these modes, the bVII subtonic is used constantly to shift away from I, and to give a kind of cadence back home to I. (this is similar to how V7 cadences to I in tonal harmony, but it is a weaker tendency, and these modal progressions sound "folky" - the minor v is very much related to bVII, but in my decades-long struggle to understand pure diatonic harmony, I almost always use bVII, and throw in the minor v as a color chord here and there)

Mixolydian tunes include: As She Moved Through The Fair, Campbell's Farewell To Redgap, B Part to Old French, The Red-haired Boy, Susan O'Dwyer ( here is great link to the progression and audio for Susan O'Dwyer http://songsinirish.com/p/siun-ni-dhuibhir-lyrics-chords.html )

A signature Mixolydian progression would be I - bVII and this is found in tons of Celtic tunes, and in quite a few Grateful Dead jams as well. For the latter, I've always used I-bVII-IV-I - I almost don't ever get sick of that!!

Aeolian tunes are always harder for me to think of, but Black Is The Color and Poor Wayfaring Stranger are two that use the minor iv - which to my ear sounds just incredibly sad!!! (yes I know that's very subjective, but in our western cultures it seems to be somewhat agreed). The first four chords to Star of the County Down are one of my favorite Aeolian progressions:

Bm - G - D - A or i - bVI - III - bVII

I've seen some discussions about Star of the County Down having some dorian tendencies and movements, but the structural bones seem to be Aeolian, unless I'm missing something....

Answer 2

I teach Celtic guitar for a living and could waffle about this subject all day, but I'll try and be brief!

As previous posters have said, Celtic music as it is played today is written in the following modes, in order of precedence:

Ionian (major scale) Dorian (optimistic minor- compared to the major scale it has ♭3 and ♭7) Mixolydian (blues-y major with a ♭7) Aeolian ("Natural minor"- darker than dorian)

As harmony instruments in Celtic music are a fairly recent addition, and much of the intonation of melody instruments like violins and keyless flutes was previously based on just intonation and the overtone series, the harmony used to accompany Celtic music tends to be fairly simple. Triads and chords containing only roots and fifths are popular choices, with more complex chords generally avoided, unless any added tones within a chord are the key's root or fifth note (of course this is not always true and there are lots of jazz infused folk players, myself included).

There are seven chords available in each mode, one for each note of its scale. One of them is a diminished chord, and these are generally avoided in folk music as they sound very unstable and clash with various features of the genre.

• For ionian tunes the main chords are Ⅰ major, Ⅳ major and Ⅴ major
• For the dorian mode the main chords used are ⅰ minor, Ⅳ major and Ⅶ major or ⅴ minor
• For the mixolydian mode the main chords used are Ⅰ major, Ⅶ major and ⅴ minor
• For the aeolian mode the main chords used are ⅰ minor, Ⅳ major and Ⅶ major or ⅴ minor.

Of course many more recent players (myself included!) like to use jazzier chords and progressions based in more modern approaches to functional harmony. It could be argued that these really have very little to do with the Celtic tradition... But they are fun!

If you would like to fully understand the modes used in Celtic music and how they influence the chords one can use with different tunes, I have a free blog on the subject here: https://finaleguitar.co.uk/how_modes_work_in_celtic_music/

I have designed a wheel which shows you each of the seven triads which will fit with a melody in any given mode- they are available here: https://finaleguitar.co.uk/product/the-amazing-mode-wheel-chord-and-key-signature-finder-tool/

My book Backing Guitar Techniques For Traditional Celtic Music gives a complete guide to how you can learn to accompany this beautiful music by ear and also discusses various approaches to harmony with numerous examples, ear training exercise, chord diagrams for the guitar and lots more: https://finaleguitar.co.uk/backing-guitar-techniques-for-traditional-celtic-music/

I also have a Youtube channel devoted to the topic, Folk Friend. Many of my videos deal with how to pick out basic harmonies by ear and then use simple substitutions, bass runs and linking chords to create fluid and fitting accompaniment. Particularly you might enjoy my music theory videos which cover the complete range of chords available in each mode and are available here: https://youtube.com/video/292o7YqWGBQ/

Finally if you are interested in the physics behind the ancient "natural" scale (overtone series based) which arguably may have been widely used in ancient Celtic music then I highly recommend the work of Dr Aindrias Hirt. This probably has little to do with harmony as the likelihood is that harmony in its modern sense was not used in Celtic music at all until long after the dilution of the "natural" scale... But if you like this sort of thing, his work is fascinating and well worth a read!

Answer 3

From a very superficial perspective, I'd say there's a lot of bVII (and perhaps minor v) resulting from the lowered subtonic in the Mixolydian and Dorian modes. Specifically, there seems to be a common back-and-forth alteration between I and bVII. Hopefully someone with better knowledge chimes in.