The McGurk Effect in Qatari Arabic: Influences of Lexicality and Consonant Position

The McGurk effect is a psycholinguistic phenomenon where an illusion is made by dubbing an auditory element of one sound on a visual element of another sound, which leads to hearing a third sound. The phenomenon demonstrates how the perception of speech does not depend on audio inputs only. Rather, it shows how seeing the shape of the mouth while producing a certain sound can influence what we hear. Thus, it proves the interaction of both vision and auditory parameters in understanding language. Also, what is known as "lexicality - the property of a word being real or not" influences speech perception. People, unconsciously, tend to alter nonwords to real words. For example, if one said "shtrength" instead of "strength", a listener would alter and understand it as "strength". For the purpose of the research, these two phenomena were combined. In this study, we test how effective is the McGurk effect on the Qatari Arabic dialect, which hasn't been investigated before. The data used were 24 minimal pairs of real and fake words with the substitution of the phonemes: /b/ and /g/ at three different positions: first, middle, final. Videos were made by dubbing audio recordings of the sound /b/ into video recordings of the sound /g/ in order to test if this creates an illusion of the sound /d/. We ran the experiment on 25 native Qatari female students, they had to sit on a computer with headphones on, watch and hear clearly what the person on the video is saying, and then they had to preform two tasks: first, lexical decision task: decide if the word is real or fake. Second, sound discrimination task: choose what sound did they hear. In general, the participants captured audio (which means they heard /b/) were only 16% of target trials, while visual capture occurred (which means they heard /g/) 45%, and the McGurk fusion (which means they heard /d/) happened on 39%. Interestingly, perceiving McGurk fusion was gradually less common at later consonants positions. A significant effect of lexicality was also found, as fusion was more likely to occur if the results of the fusion was a real word