In retrospective within-subject comparison, no core metric distinguished synthesized TTS narration from recorded instructor voice, and equivalence testing supported non-inferiority¶

Claim · All claims
Evidence · 1 study · causal r1 · q3
Currency · newest study 2026 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q3 i? When the same learners retrospectively compared instructor-voice, single TTS, and dialogue TTS lessons, no core metric showed a significant difference, and TOST equivalence testing at ±0.5 points held for all eight TTS-vs-instructor comparisons. → Gendo Kumoi 2026

Evidence¶

Gendo Kumoi 2026¶

Gendo Kumoi, Fumie Watanabe, Tota Suko, Takashi Ishida, Yuko Kuma, Manabu Kobayashi, and Shigeichi Hirasawa. (2026). A Semi-Automated System for Generating Dialogue-Based TTS Lessons Using Large Language Models: An Exploratory Study of Educational Potential. Preprint, under review at IEEE Access. https://arxiv.org/abs/2607.12235 doi:10.48550/arxiv.2607.12235

q3 · i? · causal · r1

Within-subject retrospective comparison in the Experiment 2 questionnaire (N≤183) of four core metrics across three formats; Friedman tests were non-significant with Kendall's W not exceeding .011, and TOST equivalence testing confirmed all eight comparisons "fell within the equivalence range".

"Each TTS format was compared with the instructor-voice video on each of the four metrics, and all eight comparisons fell within the equivalence range (all 𝑝 < .0001 )."

Discussion¶

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