In poetic language, in which the sign as such takes on an autonomous value, this sound symbolism becomes an actual factor and creates a sort of accompaniment to the signified.
Acoustic 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.
Linguistic sounds, considered as external, physical phenomena have two aspects, the motor and the acoustic.
Now the identification of individual sounds by phonetic observation is an artificial way of proceeding.
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.