cstr/g2p-dicts

G2P Pronunciation Dictionaries for CrispASR

IPA pronunciation dictionaries for text-to-phoneme conversion in TTS backends (piper, kokoro, melotts). Auto-downloaded by CrispASR on first use.

Pre-generated IPA Dictionaries (primary — piper-compatible)

Pre-generated IPA transcriptions matching the phoneme inventory of piper TTS models. These are factual phonetic data — word-to-IPA mappings generated by processing vocabulary lists through a phonemization engine.

File	Language	Entries	Size	Source vocabulary
espeak_en_us.tsv	English (US)	126K	3 MB	CMUdict (BSD)
espeak_de.tsv	German	667K	23 MB	open-dict-data single words
espeak_fr.tsv	French	257K	6.6 MB	OLaPh FR (MIT)
espeak_es.tsv	Spanish	600K	18 MB	OLaPh ES (MIT)

Format: word\t/IPA/ (tab-separated, IPA in slashes, one entry per line)

Benchmark: 99.5% exact match (EN) / 100% (DE) against piper model ground truth on a 382-word test set.

CMUdict (English ARPAbet — fallback)

File	Language	Entries	Source	License
cmudict.dict	English	126K	CMU Sphinx	BSD

Format: WORD PH1 PH2 PH3 (space-separated ARPAbet phonemes). CrispASR converts ARPAbet to IPA at runtime (76% piper match rate).

OLaPh Dictionaries (MIT — multilingual fallback)

File	Language	Entries	License
olaph_en_us.txt	English (US)	508K	MIT
olaph_de.txt	German	1.12M	MIT
olaph_fr.txt	French	259K	MIT
olaph_es.txt	Spanish	600K	MIT

Format: word\t/IPA/ (same as pre-generated dicts). OLaPh uses British English IPA conventions (ɐ for -er, ɒ for LOT); the pre-generated dicts above use American conventions matching piper models.

Source: iisys-hof/olaph — Becker et al., "OLaPh: Optimal Language Phonemizer", arXiv:2509.20086, MIT license.

Usage in CrispASR

Dictionaries are auto-downloaded to ~/.cache/crispasr/ on first TTS use:

# Default: uses pre-generated IPA dicts (piper-compatible)
crispasr --backend piper -m auto --auto-download --tts "Hello world" --tts-output out.wav

# Select dictionary source explicitly
crispasr --backend piper --g2p-dict cmudict --tts "Hello world" --tts-output out.wav
crispasr --backend piper --g2p-dict olaph --tts "Hello world" --tts-output out.wav

# Use a custom dictionary file
crispasr --backend piper --g2p-dict /path/to/my/dict.txt --tts "Hello world" --tts-output out.wav

Override per-language paths with environment variables:

• CRISPASR_CMUDICT_PATH — English CMUdict file
• CRISPASR_DE_DICT_PATH / CRISPASR_FR_DICT_PATH / CRISPASR_ES_DICT_PATH

Phonemization Cascade

CrispASR tries pronunciation sources in priority order:

1. Pre-generated IPA dict (99.5% piper match) — auto-downloaded
2. CMUdict + ARPAbet→IPA (EN, 76% match) / OLaPh (DE/FR/ES)
3. LTS rules (letter-to-sound, always available, zero dependencies)
4. espeak-ng via dlopen (loaded at runtime if installed on system)
5. espeak-ng via popen (subprocess fallback)

Attribution

• CMUdict: Carnegie Mellon University, BSD license. https://github.com/cmusphinx/cmudict
• OLaPh: Becker, M. et al. (2025). "OLaPh: Optimal Language Phonemizer." arXiv:2509.20086. MIT license. https://github.com/iisys-hof/olaph
• open-dict-data: CC-BY-SA 3.0 (Wiktionary-sourced). https://github.com/open-dict-data/ipa-dict

License

This dataset is released under the MIT license.

• Pre-generated IPA dicts: factual phonetic data (word→IPA mappings)
• CMUdict: BSD license
• OLaPh dicts: MIT license
• open-dict-data vocabulary (used as word source for DE): CC-BY-SA 3.0