by Gary Ewer, from “The Essential Secrets of Songwriting” website:
If you want lyrics to sound natural, you need to sing them with the natural pulses that occur in spoken language. For songwriters, you need to match up the natural pulse of the lyric with the natural flow of your music. It may not be as easy as you think, but the rewards are worth the effort.
Every language has an innate rhythm which comes across as accents and pulses, though some languages make more use of these pulses than others. For example, English has stronger accents while the pulses and accents in French are much more subtle.
Music also consists of pulses, and it’s important that songwriters make a serious attempt to match the pulses of the text with the pulses of the melodic line. If you’ve ever heard a song where you find it hard to hear the words, but they seem to be clearly spoken, mis-matched pulses between lyric and melody are usually to blame.
If you’re creating your melody and lyric together, the pulse of the text comes first in importance; modify the melody in order to make the pulse of the text work. Your song loses meaning and emotional impact if it seems that the lyric is being forced to fit the melody.
Once you’ve finished your song, take bits of the lyric and speak it(without the pitches) using the rhythm you’ve given it. Then speak the words, the way you’d normally say them in casual conversation. There should be an obvious similarity. Be sure that the notes that are longer are the ones that would normally get the most accent.
EXAMPLE: “I’m dedicated to our love.” When you say this line in casual speech, the accents are: “I’m DED-i-CA-ted to our LOVE”, with “DED” being a stronger accent than “LOVE”, and “LOVE” being stronger than “CA-“. We can actually change the meaning or inner message of what we’re talking about when we accent different words or syllables. But in whatever you do, be sure that your text pulses match up with your music pulses. This will enhance the emotional impact of your text.