Father Somerville was also a musician and composer. He wrote the Good Shepherd Mass for the English liturgy in 1965 which was adapted in 1970 for the bowdlerised Gloria and Sanctus and then corrected back by St. Michael's Choir School in 2011 with his permission. I enjoy every opportunity to sing his Responsorial Psalms in CBWII which are finely crafted based upon his authority in chant at St. Michael's Choir School. Last weekend was the 50th anniversary of his first conducting of the Tenor/Bass Choir of St. Michael's at the annual Massey Hall Christmas Concert. I have great memories of singing Handel's Messiah standing beside him in the Bass section a number of years ago in Etobicoke and singing his corrected Gloria translation (later modified by the Choir School) with him at the piano just a few years ago when visiting him at St. Bernard's Convalescent Home. Father Somerville was also the Chaplain on the set of Mel Gibson's The Passion of the Christ.
He was well-known as "Canada's liturgist" having participated on the International Committee for English in the Liturgy (ICEL) which translated the Missal of Paul VI into English from the original Latin. It is important to know that the English translation used from 1965 to 1969 of the modified 1962 Roman Missal was a faithful translation. The Novus Ordo Missae was translated by ICEL using a translation method called dynamic equivalence. Father John Zuhlsdorf began his blog from years of writing in The Wanderer highlighting the grievous textual errors in the Missal, now corrected, and which still exist in the Liturgy of the Hours.