7a. The vocal folds and voicing

     Note: Make sure that you have the Lucida Sans Unicode font installed in your computer so that the IPA symbols will display correctly. 

     The sounds of languages can be divided into voiced and voiceless or unvoiced (these two terms are used interchangeably). Vibration of the vocal cords or vocal folds produces a voiced sound. You can feel the vibrations of your vocal folds by placing your fingers over your throat while saying a sound like /zzzzzzzzz/, /vvvvvvvvvvvv/, /mmmmmmm/ or /ɑɑɑɑɑɑɑɑɑ/. But have you ever seen human vocal folds, vibrating or otherwise? It can be a bit of a jolt the first time you do. Well, get ready.

     At the following link you will see on top a picture of the vocal cords when closed (adducted) and when open (abducted); below that is a slow-motion video showing the vocal vibrating, in slow motion. This was photographed using a stroboscope, or flashing light:

http://www.medicine.uiowa.edu/otolaryngology/cases/normal/normal2.htm

    Here are some more videos of vibrating vocal folds:

http://www.voicedoctor.net/media/video/female.html

http://www.humnet.ucla.edu/humnet/linguistics/faciliti/demos/vocalfolds/vocalfolds.htm

http://www.sci.mus.mn.us/sound/vrml/vocal/vocalcu.htm

     Note how they demonstrate three ways to initiate a vowel sound: aspiration ('h'), a glottal stop, and 'zero onset', or a plain vowel. The flap of flesh you see is not the tongue. What is it?

    Here are some still pictures and a video of the larynx:

http://www.gastrolab.net/pa-212.htm

     How do you think they filmed these videos? This site shows you what a video laryngoscope is and how it works:

http://www.drpacey.com/prod01.htm

     Here is an illustration of a flexible fibre-laryngoscope; a flexible tube with a lens and light on the end of it is inserted through the nasal passage to give a view of the larynx:

http://www.dnacounter.com/dnacounter/dnac_site/endoscope_s/endos_s/laryngo/laryngoscope_1.htm

     You can see the use of both these tools demonstrated in an impressive video (towards the end) of the Acoustical Society of America (See http://asa.aip.org/videos.html). It's available in the NTU audio-visual library; here's the call number: (VC) QP306 M42z 1993 cassette 1.

     And there are now online videos of the vocals folds and of the instruments used to examine them! Embark on a 'Fantastic Voyage' here:

http://www.ncvs.org/ncvs/tutorials/youngexp/fantasticvoyage.html

     More links here:

http://www.mnsu.edu/dept/comdis/kuster4/part55.html

     Here, from the Vocal Tract Visualization Lab of the Dental School of the University of Maryland Baltimore, are some fascinating videos of what goes on when one speaks. They include a video of the legendary cartoon voice actor Mel Blanc's pharynx, and videos of Nama clicks being produced (see page II-4) , and didgeridoo playing (see page II-19).

http://www.speech.umaryland.edu/wierd.html


     Some students are surprised that the vocal folds are in fact two flaps of flesh and not one. How do you think we would sound with just one flap of flesh to produce voicing? And would speech still be possible with no vocal folds at all? Find out on the next page!


     Next: Talking with just one vocal fold, or none

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