You said "with a syllable for each note" If this what you are trying, you'll never have it right. Lots of syllables are sung over several notes. Notation usually has slurs or ties showing where it's done.

If you've really got different numbers of syllables than the original words, what others have said applies. So long as it works there's no rule against it. If you want to get compulsive, look at the notes you have and figure out where you are singing it the same & where you sing differently than the original & what you see as written. You don't have to read music well to do this. Just notice where notes are relatively longer, or shorter, repeated, an extra grace note or passing tone stuck in, or one left out. You could mark your variations if you want to.

Also remember, it's probably only choirs that sing anything just as written. Especially for transcriptions from oral tradition, the written music is really more an outline.