Photoglottography

Photoglottography or photo-electric glottography is a laboratory technique for investigating the opening and closing of the glottis in the larynx.

This cell is fixed near the end of a thin tube inserted through the nose and nasal passages (which leaves the articulators relatively free to move in speech); in the Frøkjaer-Jensen instrument the tube is extended so that a few centimetres can be swallowed into the oesophagus in order to anchor the light-sensitive cell securely in place.

A number of researchers have attempted to compare the photoglottograph output with measurements of glottal opening based on high-speed or stroboscopic film during phonation.

If the two were closely similar, the photoglottograph would represent a quicker and cheaper method of analysis of phonation.

However, Baken reports variable results: a study by Coleman and Wendahl concluded that "relating photoglottographic waveforms ... to glottal area is not only hazardous but invalid in many cases",[6] while a later study by Harden found that the photoglottograph provided "essentially the same information on glottal area function as that provided by ultrahigh-speed photography"[7] In addition to the study of vocal fold vibratory patterns, the technique may be used to detect the opening of the glottis for voiceless consonants or the closure of the glottis for glottalic consonants and glottal stop.