Automatized Vocabulary Knowledge in Predicting Speech Fluency
en-GBde-DEes-ESfr-FR

Automatized Vocabulary Knowledge in Predicting Speech Fluency

10/07/2025 Waseda University

To improve fluency, learners should move beyond memorizing words and train themselves to access words quickly and appropriately in contexts

When learning a second language (L2), many are likely familiar with the challenge of memorizing vocabulary, only to struggle with recalling and using it fluently in speech. Studies have found that speaking fluently in L2 depends not only on knowing what words mean but also on how quickly and automatically you can access and use them appropriately in contexts. This ability to retrieve contextually appropriate word meanings without conscious effort is known as automatized vocabulary knowledge (AVK).

In a new study, a team of researchers led by Mr. Kotaro Takizawa from Waseda University, Japan, along with Prof. Kazuya Saito and Dr. Yui Suzukida from University College London and Tohoku University, Mr. Satsuki Kurokawa and Dr. Takumi Uchihara from Tohoku University, Japan, compared AVK with declarative vocabulary knowledge (DVK) to explore the extent to which AVK predicts L2 utterance fluency. Their findings were published in the journal of Applied Linguistics on July 7, 2025.

“Our study addressed an outstanding question regarding the vocabulary knowledge that best supports automaticity in L2 speech production,” says Takizawa.

To investigate the relationship between each type of vocabulary knowledge and speaking fluency, the researchers assessed the AVK and DVK of 210 university students who were learning English as L2.

To evaluate DVK, participants were asked to match spoken English words with their Japanese meanings with options, capturing decontextualized word knowledge stored in memory. In contrast, AVK was evaluated by having participants listen to short English sentences and determine whether they were meaningful, testing their ability to process contextualized word meanings in real time. Next, participants took part in two speaking exercises: a narrative task based on a picture sequence and a personal monologue in response to an on-screen prompt. Further, the researchers measured fluency by analyzing three key indicators: articulation rate, which reflects how quickly a person speaks; mid-clause silent pauses, or pauses that occur within a clause; and end-clause silent pauses, which occur at the end of a clause.

Across all measures, AVK was a significantly stronger predictor of L2 speaking fluency than DVK, which showed little to no effect. Notably, mid-clause silent pauses—which indicate difficulty in linguistic encoding, such as retrieving words while speaking—were more strongly linked to AVK, suggesting that the ability to automatically access vocabulary in context plays a crucial role in fluent speech.

This finding has important implications for language learning, highlighting that fluency does not come simply from knowing more words but from sophisticating them so that they can be retrieved quickly and confidently—skills that can be developed through continuing practice and exposure to language in context. The findings suggest that learners first familiarize themselves with simple word forms and their meanings and then gradually transition to how words are used in real-world, sentence-level contexts.

“Our findings strongly support the view that building simple form-meaning connections is only the first step in L2 vocabulary learning. To become orally fluent, learners need to automatize these connections through consistent practice and meaningful exposure,” concludes Takizawa.


***


Reference
Authors:
Kotaro Takizawa1, Kazuya Saito2,3, Yui Suzukida2,3, Satsuki Kurokawa3, and Takumi Uchihara3
Title of original paper: Automatized phonological vocabulary knowledge as L2 cognitive fluency: Testing the declarative–automatized integrative model in L2 speech production
Journal: Applied Linguistics
DOI: 10.1093/applin/amaf042
Affiliations:
1Waseda University, Japan
2University College London, U.K.
3Tohoku University, Japan


About Waseda University
Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including eight prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.
To learn more about Waseda University, visit https://www.waseda.jp/top/en


About Mr. Kotaro Takizawa
Mr. Kotaro Takizawa is a Ph.D. student at Waseda University specializing in English language education and second language acquisition. His research focuses on second language speaking performance, particularly vocabulary use, oral fluency, and phraseological competence. He is a member of TESOL Quarterly’s graduate student editorial board. He has published over 10 papers in international journals and is actively involved in applied linguistics, psycholinguistics, and speech and language processing research.

Kotaro Takizawa, Kazuya Saito, Yui Suzukida, Satsuki Kurokawa, Takumi Uchihara, Automatized phonological vocabulary knowledge as L2 cognitive fluency: Testing the declarative–automatized integrative model in L2 speech production, Applied Linguistics, 2025;, amaf042, https://doi.org/10.1093/applin/amaf042
Attached files
  • Researchers revealed that the AVK is a stronger predictor of speaking fluency compared to declarative vocabulary knowledge.
10/07/2025 Waseda University
Regions: Asia, Japan, Europe, United Kingdom
Keywords: Humanities, Linguistics, Education

Disclaimer: AlphaGalileo is not responsible for the accuracy of content posted to AlphaGalileo by contributing institutions or for the use of any information through the AlphaGalileo system.

Testimonials

For well over a decade, in my capacity as a researcher, broadcaster, and producer, I have relied heavily on Alphagalileo.
All of my work trips have been planned around stories that I've found on this site.
The under embargo section allows us to plan ahead and the news releases enable us to find key experts.
Going through the tailored daily updates is the best way to start the day. It's such a critical service for me and many of my colleagues.
Koula Bouloukos, Senior manager, Editorial & Production Underknown
We have used AlphaGalileo since its foundation but frankly we need it more than ever now to ensure our research news is heard across Europe, Asia and North America. As one of the UK’s leading research universities we want to continue to work with other outstanding researchers in Europe. AlphaGalileo helps us to continue to bring our research story to them and the rest of the world.
Peter Dunn, Director of Press and Media Relations at the University of Warwick
AlphaGalileo has helped us more than double our reach at SciDev.Net. The service has enabled our journalists around the world to reach the mainstream media with articles about the impact of science on people in low- and middle-income countries, leading to big increases in the number of SciDev.Net articles that have been republished.
Ben Deighton, SciDevNet

We Work Closely With...


  • e
  • The Research Council of Norway
  • SciDevNet
  • Swiss National Science Foundation
  • iesResearch
Copyright 2025 by AlphaGalileo Terms Of Use Privacy Statement