It extends, as in the figure, from the Rolandic region (_K_), where the kinaesthetic lip-and-tongue memories of words are aroused, backward into the temporal region (_A_), where the auditory memories of words spring up; then upward to the angular gyrus in the rear or occipital region (_V_), where in turn the visual pictures of the written or printed words rise to perform their part in the performance; and with all this combination there is associated the centre for the movements of the hand and arm employed in writing, an area higher up in the Rolandic region (above _K_).

In the same general zone we also find the music function located, the musical sounds being received in the auditory centre very near the area for words heard (_A_) while the centre for musical expression is also in the Rolandic region.

Furthermore, as may be surmised, the reading of musical notation requires the visual centre, just as does the reading of words.

In addition to this, we find the curious fact that the location of the whole speech zone is in one hemisphere only.

Its location on the left or the right, in particular cases, is also an indication as to whether the person is right-or left-handed; this means that the process which makes the individual either right or left-handed is probably located in the speech zone, or near it.