This model cannot provide accurate assessments of goodness of pronunciations or provide transcripts as it is trained to be accepting of variation in pronunciation to provide a reasonable alignment for Japanese speech.

Bias, Risks, and Limitations

This model will perform best on the variety of speech that it was trained on. The speakers in the training data are all adult speakers, so child speech alignment may not be accurate.

Recommendations

When using this model on a variety that it was not trained on, better results can be attained by adapting the model to the data to be aligned first. See https://montreal-forced-aligner.readthedocs.io/en/latest/user_guide/workflows/adapt_acoustic_model.html and https://github.com/mmcauliffe/mfa-adaptation for example usage and scripts.

How to Get Started with the Model

Use the code below to get started with the model.

To get started, follow the instructions for installing MFA. To align files using this model, use the mfa align command.

Dictionary Details

Details for japanese_mfa dictionary and G2P model

Source: wikipron
Orthography: Kanji and kana
Phone set: MFA
Words: 2,239,777

Phones: 78
Graphemes: 5,752

IPA chart

Consonants

Manner	Labial	Labiodental	Alveolar	Palatal	Velar	Uvular	Glottal
Nasal	m mː		n nː	ɲ ɲː	ŋ	ɴ ɴː
Palatalized	mʲ mʲː
Stop	p pː b bː		t tː d dː	c cː ɟ ɟː	k kː ɡ ɡː		ʔ
Palatalized	pʲ pʲː bʲ		tʲ tʲː dʲ dʲː
Affricate			ts tsː dz dzː	tɕ tɕː dʑ dʑː
Sibilant			s sː z	ɕ ɕː ʑ
Fricative	ɸ ɸː	v		ç			h hː
Palatalized	ɸʲ ɸʲː	vʲ
Approximant	w			j	ɰ̃
Tap			ɾ
Palatalized			ɾʲ

Vowels

	Front	Central	Back
Close	i iː i̥	ɨ ɨː ɨ̥	ɯ ɯː ɯ̥

Close-Mid	e eː		o oː

Open-Mid

Open		a aː

Training Details

Training Data

Common Voice Japanese

Source: https://voice.mozilla.org/en/datasets
License: CC-0
Dialects: N/A
Number of hours: 71.54
Number of utterances: 56,631
Number of speakers: 1,364
- Female speakers: 199
- Male speakers: 459
- Unknown speakers: 706

GlobalPhone Japanese

Source: https://catalogue.elra.info/en-us/repository/browse/ELRA-S0199/
License: ELRA
Dialects: N/A
Number of hours: 33.88
Number of utterances: 13,103
Number of speakers: 144
- Female speakers: 44
- Male speakers: 104
- Unknown speakers: 0

Japanese Versatile Speech

Source: https://sites.google.com/site/shinnosuketakamichi/research-topics/jvs_corpus
License: CC BY-SA 4.0
Dialects: N/A
Number of hours: 30.25
Number of utterances: 14,994
Number of speakers: 100
- Female speakers: 51
- Male speakers: 49
- Unknown speakers: 100

LaboroTV Japanese

Source: https://laboro.ai/activity/column/engineer/eg-laboro-tv-corpus-jp/
License: LaboroTV Non-commercial
Dialects: N/A
Number of hours: 1,915.43
Number of utterances: 1,536,227
Number of speakers: 305,246
- Female speakers: 0
- Male speakers: 0
- Unknown speakers: 305,246

MagicData ASR-SJapDuSC

Source: https://magichub.com/datasets/japanese-scripted-speech-corpus-daily-use-sentence/
License: CC-BY-NC-ND 4.0
Dialects: N/A
Number of hours: 18.71
Number of utterances: 17,302
Number of speakers: 37
- Female speakers: 19
- Male speakers: 19
- Unknown speakers: 0

Microsoft Speech Language Translation Japanese

Source: https://msropendata.com/datasets/54813518-4ea6-4c39-9bb2-b0d1e5f0c187
License: Microsoft Research Data License
Dialects: N/A
Number of hours: 9.85
Number of utterances: 7,338
Number of speakers: 112
- Female speakers: 0
- Male speakers: 0
- Unknown speakers: 112

TEDxJP-10K

Source: https://github.com/laboroai/TEDxJP-10K
License: Apache 2.0
Dialects: N/A
Number of hours: 8.85
Number of utterances: 9,962
Number of speakers: 271
- Female speakers: 0
- Male speakers: 0
- Unknown speakers: 271

Training Procedure

Preprocessing

Preprocessing include fixes and orthographic standardization to various corpora.

Training Hyperparameters

Training regime: Training configuration

Evaluation

Testing Data, Factors & Metrics

Testing Data

N/A

Factors

N/A

Metrics

N/A

Results

N/A

Summary

Technical Specifications

Model Architecture and Objective

HMM-GMM model

Software

This model was trained via the Montreal Forced Aligner.

Citation

BibTeX:

@techreport{mfa_japanese_mfa_acoustic_2026,
	author={McAuliffe, Michael and Sonderegger, Morgan},
	title={Japanese MFA acoustic model v3.3.0},
	address={\url{https://huggingface.co/MontrealCorpusTools/japanese_mfa}},
	year={2026},
	month={Jun},
}

APA:

McAuliffe, M. & Sonderegger, M. (2026). Japanese MFA acoustic model v3.3.0. Available at https://huggingface.co/MontrealCorpusTools/japanese_mfa.

Contact

For questions and issues, please file an issue either for this model at https://huggingface.co/MontrealCorpusTools/japanese_mfa/discussions or for larger MFA issues at https://github.com/MontrealCorpusTools/Montreal-Forced-Aligner/issues.