visible speech

noun Phonetics.

1. the representation in graphic or pictorial form of characteristics of speech, as by means of sound spectrograms.
2. the system of handwritten phonetic symbols invented by Melville Bell in 1867 to provide a visually comprehensible rendition of speech sounds.

noun

1. a system of phonetic notation invented by Alexander Melville Bell (1819–1905) that utilized symbols based on the schematic representation of the articulations used for each speech sound