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.

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.

The task is to investigate speech sounds in relation to the meanings with which they are invested, i.e., sounds viewed as signifiers, and above all to throw light on the structure of the relation between sounds and meaning.

Instead of following one another the sounds overlap; a sound which is acoustically perceived as coming after another one can be articulated simultaneously with the latter or even in part before it.