1. Why sonority and intra-oral pressure?
What could be a good phonetic correlate of the sonority function? (i.e. one that can be measured and quantified)
 we are talking of scientific phonetics not taxinomic phonetics!
We thought that the sonority function would be a good correlate of the pressure measured in the vocal tract during the production of speech, because each time that there is a constriction there is also a rise of pressure (but for nasal consonants) and each time that there is an opening there is a decrease of pressure. In addition, intra oral pressure is an easily measurable and robust parameter.
What is expected then -given what we know of the sonority function- is that pressure and sonority are inversly correlated, i.e. when sonority is high, then pressure is low and vive-versa.

2. Rhytmic mandibular oscillations
The frame/content theory and rhythm
The frame/content theory of the evolution of speech production (MacNeilage 1998) stipulates that only modern humans superimpose a continual rhythmic alternation between an open and a closed mouth (a « Frame ») on the sound production process.
Rhytmic mandibular oscillations
Consonants in the closure phase
Vowels in the opening phase

3. p a p a
Pio
O.flow

4. Intraoral Air Pressure (Ps)
Consonants involve a narrowing or a ‘stricture’ at an identifiable place in the vocal tract.
For most consonants there is an increase of pressure behind the constriction leading to a clearly identifiable acoustic event when the constriction is released.
There is some evidence that Ps is a key variable. That is, it is possible that speakers adjust other physiologic parameters (such as airflow) to maintain specific air pressures for high pressure consonants (such as voiceless stops and fricatives).
It is clear that Ps observed during speech varies as a function of a large number of variables. Most of these have not been fully explored. More systematic data are needed.

6. sonoridade
pressão
intra-oral

7. Concordância: Francês: 69.1% Kinyarwanda: 52.3%
cp=0.05
[b]
[z]
[r]
[2]
[b]
[z]

8. σ\B: consoantes sonoras constrictivas
[b], [d], [g], [z], [r], [l]

9. Concordância: Francês: 81.6% Kinyarwanda: 81.6%Is Ip
Is.Ip Ic
Concordância: Francês: %
Kinyarwanda: 81.6%

10. The sonority function as established by Galves et al
The sonority function as established by Galves et al. (2002) is a mathematical concept dealing with rythmic aspects of speech.
Therefore one can ask what could be a measurable phonetic correlate of this function. Two parameters appear at first sight (ruling out amplitude):
The first is linked with biomechanical properties of the production of syllables and the second with aerodynamic parameters.
Indeed since the introduction of the Frame/content theory by MacNeilage (1998) it became clear that the cyclic alternations of jaw lowering and closing account for patterns of speech (rhyhtmic!) observed both in language acquisition and in the patterns observed in the world’s languages.

11. However even if the jaw movements are a mechanical parameter it is not easy and straightforward to obtain quantified values of these movements.
The jaw movements give rather the Frame in MacNeilage’s theory while the segmentation of the speech signal would rather account for the content and this what the sonority function accounts for.
The intraoral pressure (Ps) is the second -aerodynamic- parameter correlated to the sonority function since it accounts for the rhythmic alternations between high and low Ps

12. The results of this first work on the correlation of the sonority function and intra oral pressure clearly shows that there is a good correlation between both parameters.
It is clear that there are number of issues related to this work that have to be refined and discussed such as a finer the identification of some classes of sounds like sonorants and in particular nasals.
(A large set of quantified data giving the main statistical tendencies would not be a luxury)
However we think that the correlation between the sonority function and intra oral pressure is well established.