In the same study, Huang (2013) also studied speech production in L2 learners across different ages. In her study, she found that the age of arrival of the L2 learners had a more significant impact on speech production than on grammaticality judgement. In the speech production test, the L2 bilinguals were asked to read a paragraph aloud twice, and their speech was recorded for listeners to rate the speakers. The listeners were native English speakers from a university in Southern California, they were around 25 years old, grew up in the US, and were linguistics majors or former English teachers. The rating was done on a scale of 1 (strong perceived foreign accent) to 9 (native speaker accent), and this was to indicate the level of foreign-ness in accents of speakers in each recording. The results of the speech production ratings were such that speakers with a younger age of arrival (arrived in the US before 13 years old) scored an average of 7 to 9 on the rating of foreign accent (closer to native speaker accent), whereas speakers who arrived in the US after the age of 13 obtained average scores ranging from 1.5 to 4 (closer to strong perceived foreign accent) on the rating of foreign accent. These results show that younger L2 learners are more likely to attain native-like proficiency in speech production as opposed to older L2 learners.
In another example, a study done by James Emil Flege, Murray J. Munro, and Ian R. A. MacKay (1995) examined native Italian L2 learners of English who were immigrants living in Canada. In their study, they accessed the relation between the age of acquisition and the general degree of foreign accent in L2 learners’ production of sentences in English. In the study, participants were native Italian speakers who had begun learning English in Canada when they were between the ages of 2 to 23 years old. The average number of years that the participants have lived in Canada was 32 years. The native Italian participants were asked to produce various sentences in English. These utterances were recorded, and native English-speaking Canadian listeners were asked to rate the sentences spoken by the Italian participants on a continuous scale. There was also a control group comprising native English-speaking Canadian speakers who were asked to produce the same sentences for listeners to rate. The results of the experiment showed that a majority of the Italian participants who had started learning English after 13 years old received ratings outside of the native English range (i.e. stronger perceived foreign accent), and participants who started learning English from a younger age (between 2 years old to about 13 years old) mostly received ratings that were closer to the native English range.
Why did these researchers study accent rating? To many educators, and native speakers (like native speakers of English, for example), accent is a measure of perceived fluency and proficiency in a language. This means that the closer an L2 learner’s accent is to a native-like accent, the more fluent he/she is perceived to be. Hence, the results of the above studies show that L2 learners who started learning English as children were eventually perceived to be more orally proficient in English than L2 learners who started learning English as adults.