This was a very beautiful movie, made by the same studio that created ‘The Book of Kells’ a few years earlier. This one was set in the modern day, more or less, although it dealt with mythological themes. The story concerns a young boy named Ben who learns that his little sister Saoirse is a selkie—sort of a water spirit who can turn into a seal, but who needs to wear a certain coat in order to speak. Ben blames Saoirse for the disappearance of their mother, and for their being taken from their isolated island home to live in the dirty city with their grandmother. Music plays a large role in the movie, as Saoirse is soon discovered by a group of fairies who need her to sing a magical song that will free them from a curse placed on them by the witch Macha. Saoirse, however, is mute without her coat. She plays an ocarina-like instrument made from a shell that used to belong to her mother, but she, Ben, and their dog Cú go on an adventure to retrieve Saoirse’s coat and free the fairies.
The shell instrument is ‘voiced’ by a pennywhistle, and occasionally by two whistles playing in octaves. This gives it a much more direct sound than I would expect such an instrument to have in real life. There is no visible fipple or mouthpiece on the shell, and it is played by blowing across the open end. There are four visible fingerholes, much like an English ocarina. Using a low-pitched ocarina as the sound of the shell would have been more effective, because it would help it stand apart from the music used in the soundtrack. The ocarina also has a quiet warbling quality that definitely brings to mind the sound of deep, rippling water.
Saoirse uses the shell not only as a magical artifact, but also during a musical number featuring three fairies. They perform a version of the Irish song ‘Dúlamán’ while accompanying themselves on the tenor banjo, bodhrán, and fiddle. Saoirse uses the shell to play along on a few of the choruses. The fairies’ version of the song replaces the original’s verses with English lyrics about how they have been awaiting the arrival of a selkie to free them from Macha’s curse, and it retains the original Irish-language chorus. Dúlamán is a type of seaweed; the original song is about how the poor of Ireland would gather seaweed to eat during times of famine. It was likely chosen for its general relation to the sea and catchy tune.
(The first four measures of ‘Dúlamán’, as heard in the movie)
The movie’s titular song was written by Bruno Coulais, and sung by Lisa Hannigan. There are versions in both English and Irish, and the movie uses a combination of these. It is written to sound like an Irish folk tune, with an accompaniment of synthesized strings and percussion, guitar, harp, bouzouki, and whistle.
(The first few measures of ‘Song of the Sea’)
The first two measures of each of these songs are essentially inversions of each other—‘Dúlamán’ uses descending fourths, while ‘Song of the Sea’ uses ascending fifths. Both use the Dorian mode, and prominently feature the sixth scale degree. Between their respective modes—B and G Dorian—all pitch classes are represented except for 3. This gives the two songs a sense of ‘going together’. ‘Dúlamán’ is strictly diegetic: it only appears during the fairies’ performance, and is not even included on the movie’s soundtrack. ‘Song of the Sea’ is used both diagetically and non-diagetically throughout the entire thing.
I’m not sure if any of this would have been taken into account by the movie’s sound crew, but it is certainly interesting to look at.