Researches in expermental phonetics.
89
Of all the methods and investigations employed for determining the
mouth tone those of Hermann1 are entitled to by far the weightiest con¬
sideration. He finds for u (00) two tones, one in the first part of the
first octave and one in the second octave, for o (au), and a a tone in the
second octave which rises in pitch as 0 changes to a, for ä and ë a tone in
the second octave and one in the third octave, for Ö, ü and i a very high
tone which is in the middle of the third octave for ö, at the end of that
octave for ü and in the fourth octave for i. The octaves are numbered in
the German fashion, middle c being in the first octave. The resonance
tones for my examples of a and i are given on pages 55 and 56, and those
of some other vowels in Section III.
These data give only the approximate regions in which we may expect
to find the mouth tone. It is unquestionably true that within these regions
the mouth tone will vary for different dialects and different conditions of
speech.
The mouth tone need not be a fixed one though it is generally so. A
rise and fall of the mouth tone might readily be used as a factor of ex¬
pression in speech. Several examples of such changes have been given
in Section II.
It seems fairly well established that in addition to the cord tone there
may be several resonance tones from the mouth cavity. Lloyd dis¬
tinguishes at least two : that of the front part of the mouth (the porch
resonance) and that of the whole mouth (the fundamental resonance).2
There may be also a resonance tone from the pharynx.8 The various
vowels arise from different “radical ratios’’ between the porch tone
and the fundamental mouth tone,4 5 while it is possible to change the
pitch of both to some extent. Various other tones may arise from the
configuration of the mouth and the coexistence of the tones already
mentioned.8
Although Lloyd’s supposition of the possible presence of a number of
resonances in the mouth cavity6 * may be partly justified, yet one of these
resonances must far exceed all others in prominence in order to produce
the constancy in form and period of the resonance vibrations seen in the
'Hermann, Phonophotographische Untersuchungen, Arch. f. d. ges. Physiol. (Pflü¬
ger), 1894 LVIII 270.
2 Lloyd, Speech sounds ; their nature and causation, Phonet. Stud., 1890 III 261.
3 Lloyd, Speech sounds ; their nature and causation, Phonet. Studien, 1891 IV 294 !
also a note in Proc. Brit. Assoc., 1891 p. 796.
'Lloyd, Speech sounds ; their nature and causation, Phonet. Stud., 1891 IV 52.
5 Same, 207.
6 Lloyd, Speech sounds ; their nature and causation, Phonet. Stud., 1890 III 261;
1891 IV 52, 206.