Taiwanese is defined by the Tone Sandhi Circle. Unlike non-tonal languages such as English and Japanese, where intonation is the primary carrier of affect, Taiwanese requires ”Tonal-Safe Emotional Mapping.”
MTL is a phonetically consistent, multi-syllable orthography based on POJ. MTL is sandhi-aware, meaning the written form of a multi-syllable word reflects the tone of the front syllable after Tone Sandhi has applied. This overcame the homonym ambiguity in character-based writing system.
Historically, this system functioned as a structural checksum; our research suggests that native speakers utilize a form of ”Perfect Pitch” to decode these melodic headers. When universal AI models fail to respect this melodic continuity, intelligibility drops significantly.
By treating Taiwanese as a formal signal-processing system rather than a collection of statistical probabilities, we enable a ”Sovereign AI” that outperforms universal models in both accuracy and cultural resonance.
MTL-TTS model utilized new modeling technologies:
🗣 Y khvoax tiøh si cidee cyn zeng ee koniuu.
🗣 Y khvoax tiøh cidee cyn zeng ee koniuu.
The only difference between the above two sentences is 'si'. And yet, the 1st sentence meant: She looks like a quite lady. 2nd: He saw a quite lady.
Computers don't inherently understand the musicality of Taiwanese. The TTS system needs a robust Part-of-Speech (POS) Tagger. Not only there is scarce resources of POS in Taiwanese, and it's complexity cannot be fully covered. Traditionally, applying sandhi-rules proves it's limitation. (70% of accuracy). MTL-Tag chose labeling sentences with binary labels. 0 (tone change) and 1 (citation tone). It acts as a "script supervisor" for the AI:
Precision Tone Sandhi: Taiwanese is famous for words changing tones based on context. MTLTag pre-calculates these shifts so the AI doesn't have to guess. We continue striving for the best with POS and sandhi-rules to reduce the error percentages. Prosody Guidance: It marks where a sentence should breathe, pause, or rise in pitch, moving away from robotic, word-by-word synthesis.
Currently, we have integrated the following two Taiwanese ASRs from Hugging Face into the app for comparison:
Ideally we would like to integrate MOE's audio input method which achieved more than 95% of accuracy in providing Taiwanese 'harnji'.
We also incorporated QWen2.5 to translate English into Taiwanese 'harnji' for the pipeline process.
Why This Project Matters for the Next Generation
We have the data, we have the pipeline, and we have a model that is already "impressing the neighbors." But there is more to build.
Are you a linguist or Python developer? Help us refine our Class-based converters for KIP/POJ. Are you into ML/NLP? Help us optimize our RoBERTa/XLM tagging and loss functions (loss_mel, loss_kl, etc). Are you a Heritage Speaker? Help us review and "slice" audio to ensure the highest quality training data. Or better yet, help to design a model that can review synthesized audio file for correctness.
"I can't do this alone, but together we can fix it." Let’s ensure the language of our parents and grandparents has a seat at the table in the future of AI.
Note: The latest best model was trained from a pool of three females and one male with 28,000 sentences.