As a teacher, I became aware that there is no such thing as being 'tone deaf'.

Some people have more difficulty controlling the pitch of their voice than others, but it is control that can be learned.

They will learn best if it is not drawn to their attention too much, as self-confidence is an integral part of the 'problem'.

Make sure that the 'problem' singers are between two 'strong' singers, and they will be pulled into tune over a period of time. Use plenty of silly voice exercises - they are fun, as well as educational, and they will learn.

My experience is mostly with middle juniors, but my church choir had early teens, too.

Don't tell anyone they can't sing. A teacher told me that when I was nine, and I've never forgiven her. Now I make money from singing - so much for her opinion!!