Quote Originally Posted by gecko zzed View Post
I have recorded a few singers who have real difficulty singing a harmony.

What I have done for them is record a harmony part using an instruments (usually a piano).

I then solo this, using solo-in-front so that they can hardly heard their already recorded melody, but enough to cue them, put it in a loop and go round and round with them singing along until the latch onto it. We can get a reasonable harmony part recorded this way, even if we do it phrase by phrase.

This is also something you can do, but it depends on you being able to create that harmony part first.
I'm going to double this sentiment (see what I did there). Playing along to a piano/keyboard track is unbelievably helpful for singers who don't have a good handle on harmonies. I'll hammer out the part on a USB keyboard on a separate track, familiarize them with the notes in the context of the part, then they usually nail it pretty quickly singing along.