At what age can people differentiate sounds based on phonetic category even when such distinctions are not present in their native language? At what age does speech perception become modified?
Werker and Tees conduct experiments to determine at what age people stop differentiating sounds of different phonetic categories without the influence of their native languages. Different researchers have shown that infants can differentiate a set of phonetic sounds (Werker and Tees 49). Their ability to do this is said to reduce when they are exposed to certain linguistic experiences. It is different for adults; they perceive only the sounds that are familiar to them or exist in their native languages. Such results show that at a certain age a person’s perception of speech is modified (50). From this age, the individual’s perception matches the sounds present in their native language.
In their experiments, Werker and Tees used subjects of different native origins and age. Their age selection was determined by the subject’s exposure to their native language. During the experiment, the subjects’ speech perception was tested using sounds from certain native origins present in the experiment.
The first experiment was used to indicate that there was an actual difference in speech perception between infants and adults (51). Infants, who were English, recognized the sounds almost as well as the native speakers of that language. However, English adults performed poorly. The results clearly showed that in adulthood, cross-language speech perception declines as compared to infancy. Infants differentiate the sounds based on how they are categorized linguistically. An adult’s perception is influenced by the phonetic sounds in their native language.
The second experiment was used to determine which stage of development the ability to discriminate speech occurs. During this experiment, more adjustments were made on the subjects making the results more accurate. Infants of 10 to 12 months performed poorly than those of 6 to 8 months and 8 to 10 months (56). The experiment proved that a person’s ability to discriminate non-native sounds occurred during their first year of life. In another experiment, these results were confirmed.
The experiments by Werker and Tees show that a person’s ability to make phonetic distinctions reduces as a result of their exposure to a specific language. According to Werker and Tees, the decline occurs at the end of the first year. The speech perception ability has an effect on the process of language learning. Therefore, infants can learn different languages if their sensitivity to certain phonology is selectively tuned. Close to the end of their first-year, children understand sounds from their native language. From this point, their ability to differentiate phonetic sounds is limited.
My own Questions
The experiments by Werker and Tees clearly show that there is a decline in speech perception as one is exposed to a certain language. What is the effect on the people who can speak more than one language? Is speech perception only influenced by a person’s native language?
Also, speech perception must have an effect on people who want to learn another language. Is the ability to learn a new language related to a person’s exposure duration to other languages? Finally, the ability to discriminate phonetic sounds must have an effect on overall communication. What effect is that and what remedies, if any can language scholars or teachers make?
Werker, Janet F., and Richard C. Tees. “Cross-Language Speech Perception: Evidence for Perpetual Reorganization during the First Year of Life.” Infant Behavior and Development 7 (1984): 49-63. Print.