Speech sounds cannot be understood, delimited, classified and explained except in the light of the tasks which they perform in language.

A new era in the physiological investigation of linguistic sounds was opened up by X-ray photography.

Now the identification of individual sounds by phonetic observation is an artificial way of proceeding.

Every linguistic sign is located on two axes: the axis of simultaneity and that of succession.

Remember that the pharynx is at a crossroads from which leads off, at the top, the passage to the mouth cavity and the passage to the nasal cavity, and below, the passage to the larynx.

At first acoustics attributed to the different sounds only a limited number of characteristic features.

The search for the symbolic value of phonemes, each taken as a whole, runs the risk of giving rise to ambiguous and trivial interpretations because phonemes are complex entities, bundles of different distinctive features.