Reduce component dependence in Thai pause-placement scoring

Reduce the dependence of Thai pause-placement scoring on Thai word segmentation, CTC forced alignment, and the handling of code-switched and verbalized spans, thereby improving the accuracy and generalizability of the pause detector.

Background

The paper evaluates pause placement in Thai TTS using a composite scorer that combines Thai word segmentation, CTC forced alignment, and processing for code-switched and verbalized text spans. The authors explain that segmentation can misclassify compounds, character alignment introduces timing jitter, and the aligner lacks vocabulary for digits and Latin spans whose spoken Thai realizations therefore cannot always be localized accurately.

Because these dependencies limit the exactness of the detector, the reported pause-placement rates are considered most reliable for comparisons between systems evaluated with the same instrument. The authors explicitly leave the reduction of these component dependencies as future work.

References

The scorer is a composite of several components -- Thai word segmentation, CTC forced alignment, and the handling of code-switched and verbalized spans -- and its accuracy is bounded by all of them. Segmentation decides what counts as word-internal, and the two tokenizers we combine still agree on some compounds that a listener would treat as two words; the character aligner contributes timing jitter, and it has no vocabulary for digits or Latin spans, whose spoken Thai form it therefore cannot place. The guards described below remove the failure modes we identified, but the detector is not exact. Its rates are most reliable as comparisons between systems measured with the same instrument, and reducing these component dependencies is left to future work.

— Building and Evaluating Fixed-Voice Thai TTS from Synthetic Speech  (2609.03502 - Pipatanakul et al., 3 Sep 2026) in Appendix, Section Additional Experimental Details, subsection Prosody Pause Metric, paragraph “Scope and residual error”