'Visible speech' definitions:

Definition of 'visible speech'

(from WordNet)
noun
A phonetic alphabet invented by Melville Bell in the 19th century
noun
Spectrogram of speech; speech displayed spectrographically

Definition of 'Visible speech'

From: GCIDE
  • Visible speech \Vis"i*ble speech"\ (Phon.) A system of characters invented by Prof. Alexander Melville Bell to represent all sounds that may be uttered by the speech organs, and intended to be suggestive of the position of the organs of speech in uttering them. [Webster 1913 Suppl.]