The Role of Age of Acquisition in Late Second Language Oral Proficiency Attainment

Abstract

The current project examined whether and to what degree age of acquisition (AOA), defined as the first intensive exposure to a second language (L2) environment, can be predictive of the end state of post-pubertal L2 oral proficiency attainment. Data were collected from 88 experienced Japanese learners of English and two groups of 20 baseline speakers (inexperienced Japanese speakers and native English speakers). The global quality of their spontaneous speech production was first judged by 10 native speaking raters of English based on accentedness (linguistic nativelikeness) and comprehensibility (ease of understanding), and then submitted to segmental, prosodic, temporal, lexical, and grammatical analyses. According to the results, AOA was negatively correlated with the accentedness and comprehensibility components of L2 speech production, owing to relatively strong age effects on segmental and prosodic attainment. Yet, significant age effects were not observed in the case of fluency and lexicogrammar attainment.The results in turn suggest that AOA plays a key role in determining the extent to which learners can attain advanced-level L2 oral abilities via improving the phonological domain of language (correct consonant and vowel pronunciation, adequate and varied prosody); and that the temporal and lexicogrammatical domains of language (optimal speech rate, the proper vocabulary and grammar usage) may be enhanced with increased L2 experience, regardless of age. Whereas late second language (L2) learners tend to demonstrate a great amount of improvement in relation to increased L2 experience, especially around the early phase of second language acquisition (SLA) processes (i.e., rate of learning), many researchers have extensively examined the extent to which they can continue to enhance learners' oral ability (i.e., ultimate attainment) in a way that could lead to near nativelike proficiency. On the one hand, few bilinguals demonstrate perfect proficiency in all aspects of language like monolinguals do (Abrahamsson & Hyltenstam, 2009;Flege, Yeni-Komshian, & Liu, 1999). On the other hand, some learners are able to attain high-level L2 performance, and the incidence of successful SLA is influenced by several factors, such as the linguistic distance between first language (L1) and L2 structures

Exploring the relationship between productive vocabulary knowledge and second language oral ability

“…For example, adult L2 learners likely attain improved comprehensibility (but not necessarily reduced foreign accentedness) in accordance with increased experience (typically measured via length of residence profile), as long as they have high willingness to communicate with native and other non-native speakers (Derwing & Munro, 2013;Saito, 2015b). Whereas such experience effects can be clearly observed in the domains of suprasegmentals (Trofimovich & Baker, 2006) and fluency (Mora & Valls-Ferrer, 2012), it may require a great amount of experience (e.g., 5-10 years of immersion) to refine the sophisticated use of language (i.e., segmentals, lexical richness, grammatical complexity) (Saito, 2015a;Baker, 2010).…”

“…First, we adopted Lex30 to measure L2 productive vocabulary knowledge, as the test was validated and suggested to tap into the productive mental lexicon (Fitzpatrick & Clenton, 2010). Second, following the standards of recent L2 speech research, we elicited spontaneous speech samples via a timed picture description task (Saito, 2015a(Saito, , 2015bSaito et al, 2016), and assessed two global dimensions of L2 oral proficiencyforeign accentedness (linguistic nativelikness) and comprehensibility (ease of understanding)-and one specific aspect of L2 speech-optimal speech rate (Derwing & Munro, 2009). …”

“…The current study adopted a timed picture description task which was elaborated and designed to elicit a certain length of spontaneous speech from not only advanced and intermediate, but also beginner L2 learners (Saito, 2015a(Saito, , 2015bSaito et al, 2016). The elicited speech samples were rated by native speakers according to two global rubrics (comprehensibility, accentedness), and then submitted to fluency analyses.…”

Can corrective feedback on second language speech perception errors affect production accuracy?

“…Comparison studies of the effects of L2 speech production-focused training, L2 speech perception-focused training, and L2 speech production-perception mixed training on both modalities would be thus of future interest. It would be also interesting to replicate the current study with different age groups, such as late versus early L2 learners (Saito, 2015) and children versus adults (Baker et al, 2008); with different learning contexts, such as laboratory versus classroom settings; and with different proficiency levels. The impact of length of instruction and residence in target language countries would be worth investigating as well (Saito & Brajot, 2013;Saito & Hanzawa, 2015).…”

Which segmental features matter for successful L2 comprehensibility? Revisiting and generalizing the pedagogical value of the functional load principle

“…While research on L2 pronunciation and speech comprehensibility has usually employed some form of picture description task (Derwing and Munro, 2009;Hopp and Schmid, 2013;Isaacs and Trofimovich, 2012;Munro and Mann, 2005;Saito et al, 2015) to elicit extemporaneous speech, other aspects of L2 speech research such as fluency research (Foster and Skehan, 1996;Skehan and Foster, 1999) have demonstrated that the quality of the speech produced is attributed to the nature of a task. The impact of task type on L2 speech performance has been discussed actively in the area of fluency along with accuracy and complexity (e.g., Bygate, 1996;Ejzenberg, 1992;Skehan and Foster, 1999).…”