Pitch Dynamism Quotient is a measure of the variation a speaker has in the pitch of their voice over a length of speech. It can be considered as a measure of the ‘liveliness’ (Hincks, 2004) a speaker puts into their voice when making an oral presentation.

Pitch variation can be measured using the standard deviation, but since males and females normally have different pitch registers, a normalised value of the deviation is necessary in order to make valid comparisons.

Pitch Dynamism Quotient (PDQ) is calculated by taking the standard deviation (SD) of the pitch values (F0) of a speaker and dividing by the mean pitch level.

PDQ = SD / mean

Pitch values can be obtained from a software application such as Speech Analyzer.

Research Question

RQ: Do students of English exhibit a narrower pitch range when making oral presentations compared to ‘expert’ presenters (i.e. native lecturers)?

We might expect that students of English who do not have much experience of making oral presentations will use a narrower pitch range in their voice compared to say expert presenters such as university lecturers. This would mean the students’ presentations could be perceived as less ‘lively’, less engaging and probably more difficult to follow.

We can test this hypothesis by calculating the PDQ for a group of students while making oral presentations and compare this value to  a group of lecturers. Here are the results:

SD PDQ
Students 33.7 0.146*
Lecturers 47.1 0.230*

Comparison of pitch variation between novice and expert presenters

The students appear to have a smaller PDQ. However we need to know if this difference is statistically significant. Using a t-test we find that p<0.001 which suggest the difference is real. In other words, the novice students are using a narrower pitch range in their voice compared to the more experienced presenters. Click here to listen to a sample of this difference.

Pitch of voice has been shown to be an important structuring and cueing device when delivering oral monologues, in particular when signalling the end of a spoken paragraph (paratone) and the start of a new one. The implication then is that students, by employing a narrower pitch range, are limiting the headroom they have to make these signals to the audience.


 

Hincks, R. (2004) Processing the prosody of oral presentations. Proceedings of InSTIL/ICALL 2004 – NLP and Speech Technologies in Advanced Language Learning Systems, Venice, 63-69. http://www.speech.kth.se/prod/publications/files/1023.pdf

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