ahotts-g2p 0.1.0a2

Pure-Python, zero-dependency AhoTTS grapheme-to-phoneme (G2P) for Basque and Spanish

ahotts-g2p

Pure-Python, zero-dependency, version-aware grapheme-to-phoneme (G2P) for Basque (euskara) and Spanish, faithfully reproducing the AhoTTS text-to-speech front-end.

ahotts-g2p turns text into the single-char IPA training string used by StyleTTS2/VITS-style models, matching the AhoTTS engines that phonemized the public HiTZ Basque voices. It is stdlib-only: no C build, no shared libraries, no runtime dependencies.

Install

pip install ahotts-g2p

From source:

pip install -e .[test]

Quick start

from ahotts_g2p import phonemize

phonemize("Bai.")                                    # 'bAj .'
phonemize("Ez, horrek ez du balio!")                 # 'Eʂ , Orek eʂ tU βalIo !'
phonemize("Kaixo mundua", lang="eu", version="classic")   # 'kajʃO mundUa'
phonemize("Hola mundo.", lang="es", version="classic")    # 'Ola mUndo'

# Northern (Iparralde / Iparrahotsa) Basque dialect
phonemize("hori horrek", lang="eu", dialect="northern")   # 'hOɾi hoʁEk'

CLI:

python -m ahotts_g2p "Kaixo mundua"
cat sentences.txt | python -m ahotts_g2p

Also exported: SAMPA_TO_IPA, the ordered SAMPA -> IPA mapping table.

Versions

AhoTTS has a real engine lineage. Different public voices were phonemized by different generations, with visibly different output, so the API takes a version (classic/modern). The default is modern.

Version	Upstream source	Consuming model	Distinctive behaviour
classic	aholab/AhoTTS, original engine	HiTZ VITS voices	dictionary STR_MRK stress (original eu_dicc), vowel offglides (au -> aw)
modern	arrandi/phonemizer-eus-esp modulo1y2 + eu_dicc_20250326	HiTZ/StyleTTS2-eu	dictionary STR_MRK stress (newer dict), silent-h stress shift, ʝ palatalisation, punctuation tokens

(pyAhoTTS builds the classic engine from ekaitz-zarraga/AhoTTS, a packaging fork of aholab/AhoTTS with build/portability changes only -- no algorithmic difference.)

Full detail in docs/versions.md.

Dialects

Basque has a Northern (Iparralde) variety with its own AhoTTS engine, AhoTTS_Iparrahotsa. It is exposed as a dialect (dialect="northern", default "standard"), independent of version:

phonemize("Euskara Euskal Herriko hizkuntza da.", lang="eu", dialect="northern")
# 'Ewʂkaɾa ewʂkAl heʁIko hiskUnVa ðA'

The Northern dialect pronounces /h/, has the French vowel ü -> /y/, a uvular rhotic /ʁ/, a remapped sibilant system (s -> ʂ, z -> s, ts -> tʂ), and j/dd -> /ɟ/. It is a faithful port of the AhoTTS_Iparrahotsa fork. Full detail in docs/dialects.md.

Accuracy

Correctness is parity with the AhoTTS reference engines, measured per version on held-out corpora (positional word match):

Language	classic	modern
Spanish (es)	100%	100%
Basque (eu)	99.94%	99.90%

The Northern Basque dialect reaches 99.61% word parity (418/430 exact lines) against the AhoTTS_Iparrahotsa binary; see docs/dialects.md.

The held-out corpora ship as test fixtures, so the figures reproduce with no binaries: pytest tests/test_oracle.py. See docs/accuracy.md.

Pipeline

text -> normalize -> g2p -> syllabify -> stress -> SAMPA -> IPA -> single-char

Numbers, ordinals and roman numerals are expanded to the target-language number words; punctuation is preserved as separate tokens (modern) or dropped (classic). Per- word lexical stress and the phonetic-exception rules are driven by the decoded dictionary flags. See docs/architecture.md.

Supported languages

• Basque (eu) -- full linguistic pipeline with HDIC-dictionary POS tagging and accentual-group stress.
• Spanish (es) -- dictionary-free g2p and stress.

Where it fits

Project	Role
AhoTTS (Aholab, UPV/EHU)	upstream C++ engine; the algorithm source
pyAhoTTS	Python bindings to the AhoTTS C++ library (needs a build)
ahotts-g2p (this repo)	pure-Python reimplementation of the G2P, no build
phoonnx	downstream consumer -- ONNX TTS runtime that uses this G2P

License

GPL-3.0-or-later, matching upstream AhoTTS. This is a derivative of the GPL AhoTTS linguistic rules, so it is distributed under the same licence. The AhoTTS algorithms and dictionaries are credited to Aholab (UPV/EHU). See docs/licensing.md.