Each individual case of stuttering or stammering has its own
peculiarities, already more or less developed--arising from
structural differences (but not necessarily defects) in the organs
of speech, as well as differences in temperament, health and
nervousness; or peculiarities arising from habit--which is the
result of previous training or neglect, as the case may be.

SING WITHOUT DIFFICULTY: Almost without exception, the stutterer
or stammerer can sing without any difficulty, can talk to animals
without stuttering or stammering, can talk when alone and in some
cases can talk perfectly in a whisper. Some stammerers have less
difficulty in talking to strangers than in talking to friends or
relatives while in other cases, the condition is exactly reversed.
A stutterer or stammerer almost always experiences difficulty in
speaking over the telephone. One experimenter has shown, however,
that a stammerer can talk perfectly over the telephone so long as
the receiver hook is depressed and there is no connection with
another person at the other end of the line. This experimenter
shows that immediately the receiver hook is released and a
connection is established, the halting, stumbling utterance
begins.

These peculiarities of stuttering and stammering for many years
puzzled investigators and were, in fact, finally responsible for
arriving at the true cause of stammering.

Almost every stammerer seeks for an explanation of these peculiar
manifestations. Why is it, for instance, that a stammerer can sing
without difficulty, although he cannot talk? This is one of the