The physical changes of puberty can start as early as the age of 9 in boys, but many boys start puberty only at the age of 15. This window of change happens at different rates and it may cause teens to feel uncomfortable and insecure with their changing bodies and lack of control over them. Hormones produced in the body start a series of physical and emotional changes. Boys' voices get deeper, and as part of the process the voice may crack or squeak as the pitch goes up and down when they talk. The voice may squeak and produce other funny noises; this stage doesn't last very long, but if it happens to your teen before it does to his friends, it may be embarrassing for him. Your teen may feel different from his friends if he has started puberty at an earlier age, but that feeling will pass when the others start to catch up and go through the same changes.
There is nothing that can be done to change the stages of puberty, but parents should reassure their teen that one of the stages in the transition to becoming an adult is when their voice changes from that of a little kid to a voice more like a man. This change, together with other physical changes, may make your son feel awkward and insecure as he compares himself to his friends. This may cause stress, and parents should talk to their teen about this and other changes that are happening at the same time, so he knows that they are normal and happen to everyone.