Owain Phyfe, who sings Renaissance songs in many languages, sometimes jokes that all of the Fa la la in some songs was put in the song in place of all the
naughty bits. While this may be so, another reason for such devices is to give the listener some thinking space. As mentioned under another point, the metronome keeps ticking for a song. As a performer of
songs, you cannot just stop and stare at the audience while waiting for them to absorb what you have said. A poet reading his work can pause, but a song only stops at the end. So, when writing a song, other
devices must be used to give the audience time to get the full impact of words.
Anne Hills wrote a song about a relative of hers who was hung and then her body burned back in 1612 during the Witch Scares. Because of the nature of the song, she decided that the audience needed more time to
absorb between verses. She added a line of nonsense syllables to the beginning of each line for that purpose.
Using nonsense syllables is an old idea known by various names in different musical traditions, including: scat, mouth music, and turlutage. In some traditions there are whole songs made up of
these nonsense syllables. Those songs are actually dance tunes where the vocal rhythms are used in place of instruments or to help an instrumentalist understand and memorize the tune.
Another device for helping the audience absorb and remember a song is repetition. The chorus is one form. Some songs will have the last line of the verse repeated. Others use call and response so the
audience is repeating every line back. Any of these techniques of repetition can be used to give the audience more time to absorb.
Lyrically speaking, these devices work well for giving some thinking time. Musically speaking, a bridge can also be added.