Speechreading Based on Tye-Murray (1998) pp

Speechreading Training l Very popular in the first half of the 20th century. l Sophisticated hearing instruments and questions about the efficacy of training have reduced the emphasis on speechreading in AR programmes. l Now the emphasis is on maximising access to visual cues rather than training and practice in lip-reading.

Definitions l Lipreading: A person who relies only on the visual signal provided by the talker’s face for recognising speech. l Speechreading: The person attends to both the tracker's auditory and visual signals as well as the talker’s facial expressions and gestures, and any other available cues. (Tye-Murray, 1998)

Who will be a better speech- reader and why? l Dr E. 42 year old pharmaceutical executive with a PhD in organic chemistry. He has had a moderate bilateral hearing impairment since he was 16 years old. l Mr C. 17 year old male with normal hearing. Required to undergo an audiological evaluation prior to beginning work at at factory

Performance in speech reading tasks cannot be predicted from; l Intelligence. l Educational level. l Duration of deafness. l Onset of hearing loss. l Socio-economic status. l Verbal abilities. l Personality. (Summerfield, 1989)

What are predictors? l Gender (Dancer et al., 1994). l Age (Farrimond, 1959; Honnell et al, 1991). l Linguistic and world knowledge in children. l Jeffers and Barley (1971) also cite some characteristics that may relate to better performance such as ability to capitalise on contextual cues, willingness to guess, mental agility and willingness to revise previous interpretations.

The Difficulty of lipreading l Visibility of sounds. l Rapidity of speech. l Coarticulation and stress effects. l Talker effects. l Visemes and homophemes.

Visibility of sounds l 60% of speech sounds are not visible on the mouth or cannot be seen readily (Woodward & Barber, 1960). Consonants with high visibility are bilabials (/p, b, m, w/), labiodental fricatives (/f, v/) and linguadental fricatives (/ `, D /). l Limited visibility involve consonants produced within the mouth (/k, g, t, n/)

l Some features like voicing are not visible at all. l Vowels tend not to be visible despite some differences in lip spreading and lip rounding. l But vowels are relatively salient even with large degrees of hearing loss.

Rapidity of Speech l We speak at around syllables per minute. l That is around 15 phonemes per second. l The human eye can only register 9 or 10 discrete mouth movements per second. l Hence, the speech reader has little time to think about the identity of the word and may not even register the important movement.

Coarticulation and Stress Effects l Phonemes change in visual appearance depending on the phonetic and linguistic context l e.g. the /b/ in “beet” and “boot” l or “you” in the following question; –What did ya do yesterday? –What did YOU do yesterday?

Talker Effects l The same sound often look different when spoken by different speakers.

Visemes l Viseme: Group of speech sounds that appear identical (e.g. /p, b, m/) (Fisher, 1968). l Erber (1974) /p, b, m//l/ /f, v//w, r/ / `, D //k, g/ /n, d, t, s, z//h/

Homophemes l Homophemes: Words that look identical on the mouth. l Often not related to phonetics. l E.g. “grade” & “yes” are homophemes but “boon” and “doom” are not. l Between 40-60% of the words in English are homophenous (Berger, 1972).

Importance of Residual Hearing l The whole is greater than the sum of the parts! l Residual hearing and visual cues complement each other well.

Factors that affect the speechreading process l The talker. l The message. l The environment and communication situation. l The speechreader.

The talker l Familiarity. l Gender. –female’s speech is more recognisable –the female voice is harder for hearing impairment people to hear –male talkers may have facial hair

The Message l Structure. –length, syntactic complexity, frequency of use, similarity to other words and linguistic context l Frequency of usage. l Neighbourhoods. l Context. –e.g. “set the ________” vs “buy the _______”

The environment and communication situation l Viewing angle. l Distance. l Room conditions (e.g. lighting).

Viewing angle

Distance

Lighting

The speechreader l Innate skill. l Hearing acuity. l Emotional and physical state.

Speechreading training l It is rare that adults in rehabilitation will receive specific speechreading instruction. l The principles of speechreading will be incorporated within the larger communication management plans.

Ways to improve speechreading l Watch the talker’s lips. l Provide information to the talker about how to communicate with you. l Try to ensure that the room is well lit and you are in the optimum position. l Try to minimise background noise. l Know the topic of conversation. l Pay attention to contextual cues. l Keep a positive attitude.