Vocalise, Op. 34 No. 14 Lyrics
This song does not have words.
https://www.elyricsworld.com/vocalise,_op._34_no._14_lyrics_jackie_evancho.html
It is simply a song in which notes are sung using one`s favorite vowel sound.
Jackie`s favorite vowel sound is "ah".
This song, therefore, is composed entirely of "ah"s