{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T17:54:06Z","timestamp":1792173246059,"version":"4.4.0"},"reference-count":17,"publisher":"Public Library of Science (PLoS)","issue":"10","license":[{"start":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T00:00:00Z","timestamp":1792108800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:p>\n                    This study employed a Cumulative Link Mixed Model (CLMM) to examine the relationship between Japanese learners\u2019 filler use and OPI (Oral Proficiency Interview) level ratings. The results showed no significant association with proficiency for the\n                    <jats:italic>i<\/jats:italic>\n                    (\u3044)-group,\n                    <jats:italic>u<\/jats:italic>\n                    (\u3046)-group,\n                    <jats:italic>ano<\/jats:italic>\n                    (\u3042\u306e)-group, and\n                    <jats:italic>eeto<\/jats:italic>\n                    (\u3048\u3048\u3068)-group fillers. In contrast, the\n                    <jats:italic>a<\/jats:italic>\n                    (\u3042)-group,\n                    <jats:italic>e<\/jats:italic>\n                    (\u3048)-group,\n                    <jats:italic>o<\/jats:italic>\n                    (\u304a)-group, and\n                    <jats:italic>n<\/jats:italic>\n                    (\u3093)-group fillers were significantly negatively associated with higher proficiency, while the use of\n                    <jats:italic>maa<\/jats:italic>\n                    (\u307e\u3042)-group and\n                    <jats:italic>sono<\/jats:italic>\n                    (\u305d\u306e)-group fillers was significantly positively associated with higher proficiency. Furthermore, an analysis of\n                    <jats:italic>maa<\/jats:italic>\n                    (\u307e\u3042)-group and\n                    <jats:italic>sono<\/jats:italic>\n                    (\u305d\u306e)-group fillers based on their functions and discourse roles showed that turn-internal\n                    <jats:italic>maa<\/jats:italic>\n                    (\u307e\u3042) and inferential\/re-presenting\n                    <jats:italic>sono<\/jats:italic>\n                    (\u305d\u306e) require at least two clauses to be produced. This indicates a connection with paragraph-level language production, which is one of the criteria for \u2018Text Type\u2019 in OPI assessment. It was also found that the use of these fillers with such functions is significantly positively associated with higher proficiency. On the other hand, for fillers such as\n                    <jats:italic>ano<\/jats:italic>\n                    (\u3042\u306e) and\n                    <jats:italic>eeto<\/jats:italic>\n                    (\u3048\u3048\u3068), as well as\n                    <jats:italic>maa<\/jats:italic>\n                    (\u307e\u3042) used in adjacency pairs, no significant increase with proficiency was observed, confirming that their use is not associated with paragraph-level production. The use of fillers linked to paragraph-level production can be considered one of the key linguistic factors that can help explain the relationship between filler use and the development of oral language proficiency.\n                  <\/jats:p>","DOI":"10.1371\/journal.pone.0360747","type":"journal-article","created":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T17:31:05Z","timestamp":1792171865000},"page":"e0360747","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["The relationship between the use of fillers and Japanese proficiency: Focusing on OPI level assessment"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-2302-2218","authenticated-orcid":true,"given":"Zuohao","family":"Chen","sequence":"first","affiliation":[{"name":"The University of Osaka","place":["Osaka, Japan"],"department":["Graduate School of Humanities"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,10,16]]},"reference":[{"key":"pone.0360747.ref001","first-page":"53","article-title":"Shijishi-kei firaa \u2018ano(\u30fc)\u30fbsono(\u30fc)\u2019 no youhou [Usage of demonstrative fillers \u2018ano(\u30fc)\u2019 and \u2018sono(\u30fc)\u2019]. 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