Pronunciation of 's' sounds impacts perception of gender, researcher finds

(Medical Xpress)—A person's style of speech—not just the pitch of his or her voice—may help determine whether the listener perceives the speaker to be male or female, according to a University of Colorado Boulder researcher who studied transgender people transitioning from female to male.

The way people pronounce their "s" sounds and the amount of they use when speaking contributes to the perception of gender, according to Lal Zimman, whose findings are based on research he completed while earning his from CU-Boulder's linguistics department.

Zimman, who graduated in August, is presenting his research Jan. 5 at the annual meeting of the Linguistic Society of America in Boston.

"In the past, in the have been understood, primarily, as a biological difference," Zimman said. "I really wanted to look at the potential for other factors, other than how lowers the voice, to affect how a person's voice is perceived."

As part of the process of transitioning from female to male, participants in Zimman's study were treated with the , which causes a number of physical changes including the lowering of a person's voice. Zimman was interested in whether the style of a person's speech had any impact on how low a voice needed to drop before it was perceived as male.

What he found was that a voice could have a higher pitch and still be perceived as male if the speaker pronounced "s" sounds in a lower frequency, which is achieved by moving the tongue farther away from the teeth.

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In the following audio clips, recorded by University of Colorado Boulder researcher Lal Zimman, two transgender men say the same sentence. Both speakers’ voices have a mean pitch of 140 hertz, which is typically considered to be part of the male-sounding vocal range. But the two speakers pronounce “s” sounds differently, affecting whether their voices are perceived as male or female by the listener. In the first audio clip, a speaker called “Joe” uses low-frequency “s” sounds, and in the second clip, “Kam” uses high-frequency “s” sounds. When the clips were played for a group of 10 listeners participating in Zimman’s study, the group unanimously perceived “Joe” to be male and “Kam” to be female.

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Kam

"A high-frequency 's' has long been stereotypically associated with women's speech, as well as 's speech, yet there is no biological correlate to this association," said CU-Boulder linguistics and anthropology Associate Professor Kira Hall, who served as Zimman's doctoral adviser. "The project illustrates the socio- of pitch: the designation of a voice as more masculine or more feminine is importantly influenced by other ideologically charged speech traits that are socially, not biologically, driven."

Vocal resonance also affected the perception of gender in Zimman's study. A deeper resonance—which can be thought of as a voice that seems to be emanating from the chest instead of from the head—is the result of both biology and practice. Resonance is lower for people whose larynx is deeper in their throats, but people learn to manipulate the position of their larynx when they're young, with male children pulling their larynxes down a little bit and female children pushing them up, Zimman said.

For his study, Zimman recorded the voices of 15 transgender men, all of whom live in the San Francisco Bay area. To determine the frequency of the "s" sounds each participant made, Zimman used software developed by fellow linguists. Then, to see how the "s" sounds affected perception, Zimman digitally manipulated the recording of each participant's voice, sliding the pitch from higher to lower, and asked a group of 10 listeners to identify the gender of the speaker. Using the recordings, Zimman was able to pinpoint how low each individual's voice had to drop before the majority of the group perceived the speaker to be male.

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PeterD
1.5 / 5 (2) Jan 05, 2013
It has been my observation, from 70 years of living, that boys who have no men in their lives when they are learning to talk, tend to speak in a higher pitch.
Lena_Kiev
5 / 5 (1) Jan 06, 2013
The "s" sound is a voiceless fricative consonant. How one measures frequency of a voiceless fricative? Voiceless fricatives haven't fundamental frequency. It's widely known that testosterone grows thyroid cartilage and vocal chords. A less known fact is that testosterone also allows larynx to shift down further thus lengthening VTL (vocal tract length). I suppose that testosterone lengthens the stylohyoid ligament. VTL increase decreases frequencies of formants (peaks on spectral envelope), it's what's called "resonance". Voice doesn't really emanate from the chest, it's only seems so because taut muscles both pull larynx down and conduct vibration from larynx to chest bones. VTL increase changes spectral envelope, that could confuse the software used for measuring 'frequency of the "s" sound'. Other muscles pull larynx upwards and backwards. It's possible to learn to shift larynx upwards and backwards (for more feminine voice) or downwards (for more masculine voice).
tkjtkj
not rated yet Jan 07, 2013
Forgive me, but as i listen to each of the two voices it is certain that differences are not at all limited to the pronounciation of 's's .. Words with out 's' are idendifiably different , as my ear testifies ..
LZimman
not rated yet Jan 08, 2013
Hi Lena, I am the author of this study, and I'm happy to answer your questions, since a short news piece like this can't cover all the details of a conference paper.

First, the frequency of /s/ refers to the weighted mean frequency of the turbulent air that passes between the lips and the roof of the mouth. The mean frequency of this sound in English is in the range of 4,000-9,000 Hz, so we are not talking about fundamental frequency at all. You can read more about this in books like Ladefoged's "Elements of Acoustic Phonetics".

Second, testosterone may have some affect on the vocal tracts of transgender men. This is one of the issues I considered in my dissertation, which analyzes vocal changes undergone by 15 trans men during the early stages of testosterone therapy (search for me on ProQuest if you'd like to read about it). However, my findings as a whole pointed to the importance of articulation over biology - i.e. how speakers use the muscles you mention.

Thanks for your post!
LZimman
not rated yet Jan 08, 2013
In response to tkjtkj,

There are absolutely more factors that differ between those two example speakers besides /s/. The author of the original press release on my study asked me for a sample of two speakers who were perceived very differently despite having the same mean pitch; Kam and Joe are probably the least similar speakers in my study, as far as the sound of their voices.

However, /s/ and vocal resonance (or formants, to use technical terminology) were among the statistically significant predictors of how the voices of the 19 speakers in my study were categorized by listeners who rated their gender. The significance of /s/ was particularly robust. But I'm confident that there are other factors that go into the perception of a voice as female or male, some of which will be the subject of further investigation on my part. Thanks for bringing up this issue!
LZimman
not rated yet Jan 08, 2013
Small correction before stepping back from the keyboard: above I absentmindedly wrote "the turbulent air that passes between the lips and the roof of the mouth." I meant to say "passes between the *tongue* and the roof of the mouth."