Every linguistic sign is located on two axes: the axis of simultaneity and that of succession.
Roman JakobsonSpeech sounds cannot be understood, delimited, classified and explained except in the light of the tasks which they perform in language.
Roman JakobsonAcoustic phonetics, which is developing and increasing in richness very rapidly, already enables us to solve many of the mysteries of sound, mysteries which motor phonetics could not even begin to solve.
Roman Jakobson