Desenvolvimento linguístico das vogais baixas anteriores do inglês como L2: o papel da instrução explícita e treinamento articulatório mediada pelo ultrassom

Abstract

This dissertation addresses the role of explicit instruction and articulatory training through ultrasound imaging in the developmental process of the English low front vowels /æ/ and /ɛ/ by Brazilian learners of English as a second language (L2). Twelve data collection sessions were conducted, focusing on the acoustic production of four participants enrolled in the initial semesters of the Portuguese-English undergraduate program at the Federal University of Pelotas. The participants were exposed to visual stimuli (image presentations) to produce the target sounds in a carrier sentence. The data collections were carried out in three distinct phases: (i) initial collections, (ii) explicit instruction sessions, and (iii) final collections. Based on the Complex Dynamic Systems Theory and the concept of variability in the linguistic development process (Larsen-Freeman 1997, 2015, 2017; Hiver and Al-Hoorie 2016; Hiver, Al-Hoorie, and Evans 2021, 2022; De Bot, Lowie, and Verspoor 2017, 2021, 2022), the longitudinal data were described and analyzed using descriptive and inferential statistics to determine whether articulatory training can trigger linguistic change (Cf. Taylor, 2000; Verspoor, De Bot, and Lowie, 2011; Schereschewsky, 2021). The results showed that ultrasound-mediated articulatory training had a positive impact on vowel productions, evidenced by significant changes in formant values (F1 and F2) and vowel duration. After the training, there was a stabilization and approximation of the Brazilian Portuguese (BP) vowel productions to English vowels, particularly the vowel [æ]. Descriptive and inferential statistical analyses of the longitudinal collections revealed that vowel productions improved over time, especially for participants S2, S3, and S4, who showed progress in the quality of [æ], resembling that of the native speaker’s production, although durational differences persisted. However, participant S1 faced difficulties in distinguishing between the vowels [ε] and [æ], showing system destabilization that prevented developmental advances. These results indicate that the methodology used was effective in improving vowel production, and the longitudinal analysis through the Complex Dynamic Systems Theory was essential for understanding the developmental trajectory of vowel productions and the impacts of explicit instruction and ultrasound-mediated articulatory training on the variability of the phonetic-phonological system.