---
title: "The Chulalongkorn Corpus of Spoken Thai — Pittayaporn 2026"
description: "Research on sociotonetics, the study of how lexical tone varies socially, has seldom used spontaneous speech, partly because annotating it takes so much…"
authors: ["Pittayawat Pittayaporn", "Cathryn Yang", "Sujinat Jitwiriyanont", "James Kirby"]
year: 2026
venue: "Proceedings of the Fifteenth Language Resources and Evaluation Conference"
source: "https://aclanthology.org/2026.lrec-1.247/"
doi: "10.63317/3ds35jijmgrx"
licence: "CC BY-NC 4.0 (ELRA, LREC proceedings)"
licence_url: "https://creativecommons.org/licenses/by-nc/4.0/"
summary_licence: "Elamur Cosmic License"
canonical: "https://research.elamur.ai/free/en/papers/pittayaporn-2026-chulalongkorn-corpus-spoken-thai-ccost/"
---
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# The Chulalongkorn Corpus of Spoken Thai (CCOST)

**Authors:** Pittayawat Pittayaporn, Cathryn Yang, Sujinat Jitwiriyanont, James Kirby · **Year:** 2026 · **Venue:** Proceedings of the Fifteenth Language Resources and Evaluation Conference · **Licence:** [CC BY-NC 4.0 (ELRA, LREC proceedings)](https://creativecommons.org/licenses/by-nc/4.0/)

**Links:** [Publisher's page](https://aclanthology.org/2026.lrec-1.247/) · [PDF](https://aclanthology.org/2026.lrec-1.247.pdf) · [DOI 10.63317/3ds35jijmgrx](https://doi.org/10.63317/3ds35jijmgrx) · [OpenAlex](https://openalex.org/W7160102400)

**Citations:** 0 citations (openalex-snapshot · 2026-10-14)

## Summary
Research on sociotonetics, the study of how lexical tone varies socially, has seldom used spontaneous speech, partly because annotating it takes so much effort. Thai lacks suitable data. Existing Thai speech corpora were built mainly for ASR, mostly contain read speech, and offer no phonetic-level annotation of unscripted talk. CCOST addresses this gap for Standard Thai. Trained Chulalongkorn linguistics students recorded speakers from several regions in semi-structured interviews adapted from Tagliamonte's schedule. Speakers also completed two tone-focused reading tasks: a monosyllabic wordlist and a sentence set replicating Gandour et al.'s tonal coarticulation design. The annotation pipeline ran Google ASR inside OCTRA, then manual correction, then BAS MAUS segmentation. Phonetically trained native speakers checked the output, which has time-aligned word, syllable, phone and toneme tiers. Each file is graded for audio quality and, for reading tasks, for pacing. The corpus is a rare resource for a tone language outside the Sinitic family. It supports analysis of tonal and segmental variation by age, gender and region, and its hand-corrected alignments can improve forced alignment for Thai.

## Key points
- The corpus holds about 7 hours of interview speech from 49 speakers (19 male, 30 female), aged 18–83 (mean 40, median 29). Of these, 27 come from Greater Bangkok and the rest from Central, Northeastern, Northern and Southern regions.
- Each speaker read a 206-item monosyllabic wordlist twice and 25 sentences three times. The wordlist crosses the five tones with onset type, syllable structure and vowel length.
- Recordings were made between January 2020 and March 2023 (none in 2021 because of COVID) at 44.1 kHz, 16-bit WAV.
- The processing chain was CHUNKPREP → G2P → MAUS → PHO2SYL, producing TextGrid tiers such as ORT, KAN and KAS.
- Files are graded A/B/C for quality using a Praat script for signal-to-noise ratio (SNR) plus human spot checks. A file is flagged if SNR is below 10 dB or mean intensity is below 45 dB. Data and metadata are on Zenodo (doi:10.5281/zenodo.17366698).

*Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.*

Fields: [Linguistics & languages](https://md.research.elamur.ai/free/en/shelves/linguistics/)

## Cite

The paper itself, not this page. BibTeX from the library's record of the work.

```bibtex
@inproceedings{pittayaporn2026chulalongkorn,
  title = {{The Chulalongkorn Corpus of Spoken Thai (CCOST)}},
  author = {Pittayaporn, Pittayawat and Yang, Cathryn and Jitwiriyanont, Sujinat and Kirby, James},
  booktitle = {Proceedings of the Fifteenth Language Resources and Evaluation Conference},
  year = {2026},
  doi = {10.63317/3ds35jijmgrx},
  url = {https://doi.org/10.63317/3ds35jijmgrx}
}
```

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