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Dr Kazuya Saito

PhD in Second Language Acquisition (McGill University, Canada)
MA in Linguistics (Syracuse University, US)

Contact details

Department of Applied Linguistics and Communication
Birkbeck, University of London
26 Russell Square,


Research and teaching


  • My research interests cover a wide range of topics in Second Language Acquisition (SLA), Education, and Psycholinguistics. Specifically, I am interested in the assessment, development, and teaching of adult second language (L2) speech.
  • Find me on Google Scholars and Research Gate.

Thesis Supervision/Research Training

  • I have taught the following courses at Birkbeck:
    • Language Learning (BA)
    • Investigating Language (BA) (team-taught)
    • Second and Additional Language Acquisition (MA) (co-taught with Jean-Marc Dewaele)
    • Linguistic Description for Language Teaching (MA) (co-taught with Bojana Petrick)
    • Introduction to Applied Linguistics (MA) (team-taught)
  • Areas of research supervision
    • Second language acquisition
    • Second and foreign language teaching
    • Second language speech (pronunciation, fluency, vocabulary, grammar) learning
    • Effects of instruction (corrective feedback; task; input; output; interaction)
    • Age and experience effects on second language acquisition
    • Aptitude and motivation in second language acquisition
      Second language assessment and testing
    • Second language speech perception and production
    • Pronunciation teaching
    • Fluency training
    • Listening teaching
    • Vocabulary teaching
  • Current Students
    • Hui Sun (2015-, PhD co-supervision with Dr. Jean-Marc Dewaele, Birkbeck, University of London)
      • How much does cultural background predict the L2 oral proficiency development of ESL learners study abroad
    • Yukie Saito (2015-, PhD Independent Research, Temple University, Japan Campus)
      • Effects of suprasegmental-based instruction on second language comprehensibility in meaning-oriented classrooms
  • I have served as an examiner on 8 PhD and MA thesis committees (2013-2015) in Japan and Canada.

Ongoing Research Projects

How to Assess L2 Speech?

  • Given the significance of L2 speech assessment, much research attention has been directed towards how native speakers perceive and process second language (L2) learners’ accented speech for the purpose of successful communication. My research has analyzed which linguistic errors are relatively detrimental (or unrelated) to native speakers’ intuitive judgements of comprehensibility (i.e., ease of understanding) in L2 speech.
    • Measuring important pronunciation features of comprehensible L2 speech
      In collaboration with Pavel Trofimovich (Concordia University, Canada), Talia Isaacs (University of Bristol) and Dustin Crowther (Michigan State University, US), I have investigated the role of phonological information in native speakers’ comprehensibility assessment in three contexts: Francophone learners in Montreal (Saito et al., in press), Japanese learners of English in Canada (Saito et al., 2015), and a range of ESL students in Montreal (Crowther et al., 2015a, 2015b).
    • Measuring important vocabulary features of comprehensible L2 speech
      To further expand this vein of L2 speech research, I have also examined diverse domains of lexical usage (e.g., appropriateness, fluency, variation, sophistication, abstractness, sense relations) in comprehensible L2 speech. The research team consisted of Stuart Webb (Western University, Canada), Pavel Trofimovich (Concordia University, Canada), and Talia Isaacs (University of Bristol). Our work will be published in several venues (e.g., Saito et al., 2016, 2017).
    • Monolingual vs. multilingual raters’ perception of L2 speech
      Natsuko Shintani (University of Auckland, NZ) and I have corroborated on how native speakers with different backgrounds (e.g., multilinguals vs. monolinguals, linguists vs. non-linguists) differentially perceive L2 speech. In particular, we are interested in these expert vs. novice raters’ processing of phonological, lexical and grammatical information during their L2 speech assessment. Our work will be published in several venues (e.g., Saito & Shintani, in press).
    • Human judgements of L2 speech
      In order to develop and validate more practical, intuitive, and efficient ways of measuring L2 speech, Pavel Trofimovich, Talia Isaacs, and I have worked on examining whether and to what degree human raters (with and without pedagogical/linguistic backgrounds) can be trained to reliably assess multiple dimensions of L2 speech (e.g., segmentals, prosody, rhythm, fluency, lexical appropriateness/richness, grammatical accuracy/complexity), which have traditionally been analyzed by computerized acoustic and corpus-based instruments. We elaborated a rater training procedure as well as a computerized L2 speech assessment program, Z-LAB.
      Find a programing code for our Z-LAB Software (
      See our validation and generalization study (Saito et al., in press)
    • Acoustic analyses of L2 speech
      As a part of various collaborations with Murray Munro, Tracey Derwing and Xianghua Wu (Simon Fraser University, Canada), I have worked on the modeling of the acoustic characteristics of L2 speech, specifically English vowels (Munro, Derwing, & Saito, 2013), English approximants (Saito & Munro, 2014) and Mandarin tones (Saito & Wu, 2014).

How does L2 Speech Acquisition Occur?

  • The second objective of my research program is to examine how adult L2 learners can enhance the linguistic qualities of their speech production in naturalistic (e.g., immigrants) and classroom (e.g., EFL education, CLIL) contexts.
    • Naturalistic L2 speech learning
      I have investigated how highly motivated Japanese learners of English with different lengths of residence (0 to 40 years) and ages of acquisition (16 to 40 years) can differentially improve their L2 speech in terms of segmentals (e.g., Saito, 2013) and overall oral proficiency (e.g., Saito, 2015a, 2015b). The findings will shed some light on theoretical debates regarding the underlying mechanism of late bilingualism (e.g., Critical Period Hypothesis).
    • Instructed L2 speech learning
      In collaboration with Keiko Hanzawa (Waseda University, Tokyo), I have taken a longitudinal approach towards investigating the extent to which, and in what ways, one academic year of foreign language classroom experience can facilitate the L2 oral proficiency development of 50+ first-year Japanese college students enrolled in traditional EFL (3 hours per week) and CLIL (15 hours per week) programs (which have different degrees of focus on form and meaning). Our work will be disseminated through publication (e.g., Saito & Hanzawa, in press).
    • Individual differences
      Recently, I have also become interested in how the extensive variability in L2 students’ learning outcomes, especially in classroom SLA, can be attributed to a range of individual difference factors, such as integrative vs. instrumental motivation and explicit vs. implicit language learning aptitude.

How to Teach L2 Speech?

  • The third objective of my research program delves into how to optimize adult L2 learning processes via various types of focus-on-form instructional options (e.g., explicit vs. implicit, comprehension- vs. production-based) in meaning-oriented classrooms.
    • Explicit instruction
      I have extensively examined how explicit instruction (i.e., providing metalinguistic explanation on target phonological features) can impact the development of L2 speech perception and production skills through intervention studies with more than 100 ESL and EFL students in the US and Japan (e.g., Saito, 2011, 2012, 2013, 2015).
    • Corrective feedback (recasts)
      One intriguing way of drawing L2 learners’ attention to grammatical and lexical accuracy during meaning-oriented classrooms concerns the provision of corrective feedback (especially as a form of recasts). In collaboration with Roy Lyster (McGill University, Canada), I have tested whether this technique can impact L2 phonological acquisition (e.g., Saito, 2013; Saito & Lyster, 2012a, 2012b). We have also published a narrative as well as meta-analytic review on the role of corrective feedback in classroom SLA (e.g., Lyster & Saito, 2010)
    • Longitudinal effects of focus-on-form
      Few practitioners and researchers disagree with the fundamental idea that conversational experience with native (and non-native) speakers contributes to L2 development to a great degree. Yet, no empirical studies have ever examined such an interaction-acquisition link from a longitudinal perspective. Yuka Akiyama (Georgetown University, US) and I have tracked the development of aural and oral ability of Japanese EFL college students engaged in weekly, one-hour conversation exchanges with native speakers in US via Google Hangout over one academic semester.


Publications in Refereed Journals

  • Saito, K., & Akiyama, Y. (in press, 2017). Video-based interaction, negotiation for comprehensibility, and second language speech learning: A longitudinal study. Language Learning
  • Saito, K., Trofimovich, P., & Isaacs, T. (in press, 2017). Using listener judgements to investigate linguistic influences on L2 comprehensibility and accentedness: A validation and generalization study. Applied Linguistics. doi: 10.1093/applin/amv047
  • Saito, K., & Hanzawa, K. (in press, 2017). Developing second language speaking proficiency in foreign language classrooms: The role of the length and focus of instruction and individual differences. Applied Psycholinguistics. Advance online publication. doi: 10.1017/S0142716415000259
  • Saito, K., Webb, S., Trofimovich, P., & Isaacs, T. (in press, 2017). Lexical profiles of comprehensible second language speech: The role of appropriateness, fluency, variation, sophistication, abstractness and sense relations. Studies in Second Language Acquisition, 38. Advance online publication. doi: 10.1017/S0272263115000297
  • Saito, K., Webb, S., Trofimovich, P., & Isaacs, T. (in press, 2016). Lexical correlates of second language speaking proficiency: Comprehensibility versus accentedness. Bilingualism: Language and Cognition. Advance online publication. doi: 10.1017/S1366728915000255
  • Saito, K., & Shintani, N. (in press, 2016). Do native speakers of North American and Singapore English difference perceive second language comprehensibility? TESOL Quarterly. Advance online publication. doi: 10.1002/tesq.234
  • Saito, K., Trofimovich, P., & Isaacs, T. (in press, 2016). Second language speech production: Investigating linguistic correlates of comprehensibility and accentedness for learners at different ability levels. Applied Psycholinguistics.  Advance online publication. doi: 10.1017/S0142716414000502
  • Trofimovich, P., Isaacs, T., Kennedy, S., Saito, K., & Crowther, D. (in press, 2016). Flawed self-assessment: Investigating self- and other-perception of second language speech. Bilingualism: Language and Cognition. Advance online publication. doi: 10.1017/S1366728914000832
  • Saito, K. (2015a). The role of age of acquisition in late second language oral proficiency attainment. Studies in Second Language Acquisition, 37, 713-743
  • Saito, K. (2015b). Experience effects on the development of late second language learners’ oral proficiency. Language Learning, 65, 563-595.
  • Saito, K. (2015c). Communicative focus on L2 phonetic form: Teaching Japanese learners to perceive and produce English /ɹ/ without explicit instruction. Applied Psycholinguistics, 36, 377-349.
  • Saito, K. (2015d). Variables affecting the effects of recasts on L2 pronunciation development. Language Teaching Research, 19, 276-300.
  • Crowther, D., Trofimovich, P., Saito, K., & Isaacs, T. (2015). Second language comprehensibility revisited: Investigating the effects of learner background. TESOL Quarterly, 49, 814-837.
  • Crowther, D., Trofimovich, P., Isaacs, T., & Saito, K. (2015). Does task affect second language comprehensibility? Modern Language Journal, 99, 80-95.
  • Saito, K. (2014). Experienced teachers' perspectives on priorities for improved intelligible pronunciation: The case of Japanese learners of English. International Journal of Applied Linguistics, 24, 250-277.
  • Saito, K., & Munro, M. (2014). The early phase of /ɹ/ production development in adult Japanese learners of English. Language and Speech, 57, 451-469.
  • Saito, K., & Wu, X. (2014). Communicative focus on form and L2 suprasegmental learning: Teaching Cantonese learners to perceive Mandarin tones. Studies in Second Language Acquisition, 36, 647-680.
  • Saito, K. (2013a) Age effects on late bilingualism: The production development of /ɹ/ by high-proficiency Japanese learners of English. Journal of Memory and Language, 69, 546-562.
  • Saito, K. (2013b). The acquisitional value of recasts in instructed second language speech learning: Teaching the perception and production of English /ɹ/ to adult Japanese learners. Language Learning, 63, 499-529.
  • Saito, K. (2013c). Re-examining effects of form-focused instruction on L2 pronunciation development: The role of explicit phonetic information. Studies in Second Language Acquisition, 35, 1-29.
  • Saito, K., & Brajot, F. (2013). Scrutinizing the role of length of residence and age of acquisition in the interlanguage pronunciation development of English /ɹ/ by late Japanese bilinguals. Bilingualism: Language and Cognition, 16, 847-863.
  • Lyster, R., Saito, K., & Sato, M. (2013). Oral corrective feedback in second language classrooms. Language Teaching, 46, 1-40.
  • Saito, K. (2012).Effects of instruction on L2 pronunciation development: A synthesis of 15 quasi-experimental intervention studies. TESOL Quarterly, 46, 842-854.
  • Saito, K., & Lyster, R. (2012a). Effects of form-focused instruction and corrective feedback on L2 pronunciation development of /ɹ/ by Japanese learners of English. Language Learning, 62, 595-633.
  • Saito, K., & Lyster, R. (2012b). Investigating pedagogical potential of recasts for L2 vowel acquisition. TESOL Quarterly, 46, 387-398.
  • Saito, K., & van Poeteren, K. (2012). Adjustment strategies for intelligibility in L2 teacher talk: Results and implications of a questionnaire study. Language Awareness, 21, 369-385.
  • Saito, K. (2011a). Identifying problematic segmental features to acquire comprehensible pronunciation in EFL settings: The case of Japanese learners of English. RELC Journal, 42, 358-373.
  • Saito, K. (2011b). Examining the role of explicit phonetic instruction in native-like and comprehensible pronunciation development: An instructed SLA approach to L2 phonology. Language Awareness, 20, 45-59.
  • Saito, K. (2011c). Differential effects of phonological and lexicogrammatical errors on NS and NNS listeners’ perceptions of comprehensibility: An exploratory study. The Journal of Asia TEFL, 8, 39-61.
  • Lyster, R., & Saito, K. (2010a). Corrective feedback in classroom SLA: A meta-analysis. Studies in Second Language Acquisition, 32, 265-302.
  • Lyster, R., & Saito, K. (2010b). Interactional feedback as instructional input: A synthesis of classroom SLA research. Language, Interaction and Acquisition, 1, 276-297.
  • Saito, K. (2007). The influence of explicit phonetic instruction on pronunciation teaching in EFL settings: The case of English vowels and Japanese learners of English, Linguistic Journal, 3(3), 17-41.

Publications in Book Chapters and Conference Proceedings

  • Saito, K. (in press). Recasting. In Liontas, J. (Ed.), The TESOL encyclopedia of ELT. Wiley-Blackwell.
  • Saito, K., Trofimovich, P., Isaacs, T., & Webb, S. (in press). Re-examining phonological and lexical correlates of second Language comprehensibility: The role of rater experience. In. J. T. Isaacs & P. Trofimovich (Eds.). Interfaces in second language pronunciation assessment: Interdisciplinary perspectives. Bristol, UK: Multilingual Matters.
  • Saito, K. (2015). Review of Teaching and Researching English Accents in Native and Non-native Speakers edited by Ewa. Waniek-Klimczak and Linda. Shockey (2013, Springer). World Englishes, 33, 293-295.
  • Saito, K. (2015). How do non-native speakers perceive the role of phonology and leixogrammar in improved comprehensibility? Waseda Culture Review, 46, 63-75.
  • Munro, M. J., Derwing, T. M., & Saito, K. (2013). English L2 vowel acquisition over seven years. In. J. Levis & K. LeVelle (Eds.). Proceedings of the 4th Pronunciation in Second Language Learning and Teaching Conference, Aug. 2012. (pp. 112-119). Ames, IA: Iowa State University.

Publications in Instructional Resources

  • One-time submissions
    • Isaacs, T., Crowther, D., Trofimovich, P., & Saito, K. (2014). Learning to speak English? Making yourself understood isn’t all about the accent. The Conversation.
    • Saito, K., & MacKay, D. (2011). What characterizes intelligible pronunciation? The case of 10 experienced non-native speakers in Canada. The English Journal, 41(3), 22-35.
    • Saito, K. (2009). How to learn and practice eight English-specific sounds in English. The English Journal, 39(1), 24-32.
  • Monthly submissions
    • Saito, K. (March 2011– March 2019). Learning intelligible pronunciation. In Hearing Marathon. Tokyo: ALC press.
    • Saito, K. (February 2009 – February 2011). Introduction to English pronunciation. In Hearing  Marathon. Tokyo: ALC press.
      • Description of the publication
        • In the magazine entitled Hearing Marathon, published monthly by ALC Press (Tokyo, Japan) to which more than 50,000 learners as well as teachers subscribe, I have had the opportunity to write articles monthly to provide research-based information to improve their pronunciation learning/teaching methods.


  • I have served as a reviewer for the following journals:
    • International Journal of Bilingual Education and Bilingualism, Routledge. (2015)
    • Language Teaching, Cambridge University Press. (2013, 2014, 2015)
    • Language Learning, Wiley-Blackwell. (2009, 2010, 2015)
    • Language Awareness, Routledge. (2015)
    • Classroom Discourse, Routledge. (2015)
    • Second Language Research, SAGE. (2015)
    • Language Teaching Research, SAGE. (2011, 2013, 2015)
    • Language and Speech, SAGE. (2014, 2015)
    • Journal of Second Language Pronunciation, John Benjamins (2015)
    • Studies in Second Language Acquisition, Cambridge University Press. (2014)
    • TESOL Quarterly, Wiley-Blackwell. (2011, 2012, 2013, 2014)
    • The Modern Language Journal, Wiley-Blackwell. (2011, 2012, 2014)
    • Applied Linguistics, Oxford University Press. (2011, 2014)
    • Canadian Modern Language Review, University of Toronto Press. (2012, 2014)
    • Journal of Immersion and Content-Based Language Education, John Benjamins. (2013)
    • Speech Communication, Elsevier. (2013)
    • Journal of Speech Sciences, LBASS. (2013)
    • TESL Canada Journal, TESL CANADA. (2013)
    • System, Elsevier. (2009, 2010, 2012)