Singing fingers

There is a beautiful song (really, one of many beautiful songs) in the French film Les Choristes called "La Nuit" ("The Night") which I love.  I was looking on youtube for a version of the song with the lyrics displayed.  I found a highly-viewed one, but it contained some errors.  My favorite error was their assertion that the line was "Si doux est le concert de tes doigts chantant l'espérance," which means, "So soft is the concert of your fingers singing hope."  The real line is "So soft is the concert of your voices singing hope."  The word for fingers, 'doigts,' sounds like "dwah" and the word for voices, 'voix' sounds like "vwah," so they are easily confused aurally.  But I don't know why someone would think that the line was about singing fingers.