corpusgen 0.1.0

Language-agnostic framework for generating and evaluating speech corpora with maximal phoneme coverage

corpusgen

Language-agnostic framework for generating and evaluating speech corpora with maximal phoneme coverage.

corpusgen helps you build phonetically-balanced text corpora for speech synthesis (TTS), speech recognition (ASR), and clinical speech assessment — in any language.

Features

• Evaluate any text corpus for phoneme, diphone, or triphone coverage

• PHOIBLE integration — phoneme inventories for 2,186 languages (3,020 inventories)

• Grapheme-to-phoneme via espeak-ng for 100+ languages

• Espeak ↔ PHOIBLE mapping — seamless bridge between G2P and phonological databases

• Structured reports — three verbosity levels, JSON export, JSON-LD-EX compatibility

• 40-language test suite — validated across 12 language families

• 6 selection algorithms for corpus optimization:

  • Greedy Set Cover — ln(n)+1 approximation, the standard workhorse
  • CELF — lazy evaluation speedup, identical results up to 700× faster
  • Stochastic Greedy — (1-1/e-ε) approximation, scales to massive corpora
  • ILP — exact optimal solutions via Integer Linear Programming (ground truth)
  • Distribution-Aware — KL-divergence minimization for frequency matching
  • NSGA-II — multi-objective Pareto optimization (coverage × cost × distribution)

• Phoneme weighting — uniform, frequency-inverse, and linguistic class strategies

• Phon-CTG generation framework — orchestrated corpus generation with pluggable backends:

  • Repository backend — select from sentence pools (pre-phonemized, raw text, or HuggingFace datasets)
  • LLM API backend — generate targeted sentences via OpenAI/Anthropic/Ollama (BYO API key)
  • Local model backend — HuggingFace transformers with CUDA auto-detect and 4-bit/8-bit quantization

• Phon-DATG — inference-time logit steering for phonetically-targeted local generation

• Phon-RL — PPO-based policy fine-tuning with composite phonetic reward (custom implementation, no trl dependency)

Coming Soon

• CLI — command-line interface for all operations

Prerequisites

espeak-ng (required)

corpusgen uses espeak-ng for grapheme-to-phoneme conversion. Install it before using corpusgen.

Windows

1. Download the latest .msi installer from espeak-ng releases
2. Run the installer (default path: C:\Program Files\eSpeak NG\)
3. Set the environment variable so Python can find the shared library:

[Environment]::SetEnvironmentVariable("PHONEMIZER_ESPEAK_LIBRARY", "C:\Program Files\eSpeak NG\libespeak-ng.dll", "User")

4. Restart your terminal and verify:

espeak-ng --version

macOS

brew install espeak-ng

Linux (Ubuntu/Debian)

sudo apt-get update && sudo apt-get install -y espeak-ng

Docker / CI

RUN apt-get update && apt-get install -y espeak-ng && rm -rf /var/lib/apt/lists/*

PHOIBLE data (recommended)

To use PHOIBLE phoneme inventories (2,186 languages), download the data on first use:

from corpusgen.inventory import PhoibleDataset
PhoibleDataset().download()  # cached at ~/.corpusgen/phoible.csv (~24 MB)

This only needs to be done once.

Installation

From PyPI

pip install corpusgen

Development setup

git clone https://github.com/jemsbhai/corpusgen.git
cd corpusgen
poetry install
poetry run pytest

With local model support (GPU recommended)

For Phon-RL training and Phon-DATG logit steering with local models:

# 1. Install corpusgen with local model dependencies
poetry install --with local

# 2. IMPORTANT: Replace CPU torch with CUDA torch for GPU acceleration.
#    The default Poetry install pulls CPU-only torch from PyPI.
#    For NVIDIA GPUs (CUDA 12.1):
pip install torch --index-url https://download.pytorch.org/whl/cu121 --force-reinstall

# Verify GPU is available:
python -c "import torch; print(f'CUDA: {torch.cuda.is_available()}, Device: {torch.cuda.get_device_name(0) if torch.cuda.is_available() else \"N/A\"}')"

Note: Check pytorch.org/get-started for the correct CUDA version matching your driver. Common options: cu118, cu121, cu124.

Quick Start

Evaluate a corpus for phoneme coverage

import corpusgen

report = corpusgen.evaluate(
    ["The quick brown fox jumps over the lazy dog.",
     "She sells seashells by the seashore.",
     "Pack my box with five dozen liquor jugs."],
    language="en-us",
    target_phonemes="phoible",
)

print(report.render())
print(report.coverage)           # 0.65
print(report.missing_phonemes)   # {'ʒ', 'ð', 'θ', ...}

Select optimal sentences from a candidate pool

import corpusgen

candidates = [
    "The quick brown fox jumps over the lazy dog.",
    "She sells seashells by the seashore.",
    "Peter Piper picked a peck of pickled peppers.",
    "How much wood would a woodchuck chuck?",
    "To be or not to be, that is the question.",
]

result = corpusgen.select_sentences(
    candidates,
    language="en-us",
    algorithm="greedy",  # or "celf", "stochastic", "ilp", "distribution", "nsga2"
)

print(f"Selected {result.num_selected} of {len(candidates)} sentences")
print(f"Coverage: {result.coverage:.1%}")

Generate a corpus from a sentence pool (Phon-CTG + Repository)

from corpusgen.generate.phon_ctg.targets import PhoneticTargetInventory
from corpusgen.generate.phon_ctg.scorer import PhoneticScorer
from corpusgen.generate.phon_ctg.loop import GenerationLoop, StoppingCriteria
from corpusgen.generate.backends.repository import RepositoryBackend
from corpusgen.g2p.manager import G2PManager

# 1. Phonemize a sentence pool
g2p = G2PManager()
sentences = ["The cat sat on the mat.", "Big dogs bark loudly.", ...]
results = g2p.phonemize_batch(sentences, language="en-us")
pool = [
    {"text": s, "phonemes": r.phonemes}
    for s, r in zip(sentences, results) if r.phonemes
]

# 2. Set up targets, scorer, and backend
targets = PhoneticTargetInventory(
    target_phonemes=["p", "b", "t", "d", "k", "g"],
    unit="phoneme",
)
scorer = PhoneticScorer(targets=targets, coverage_weight=1.0)
backend = RepositoryBackend(pool=pool)

# 3. Run the generation loop
loop = GenerationLoop(
    backend=backend,
    targets=targets,
    scorer=scorer,
    stopping_criteria=StoppingCriteria(
        target_coverage=0.9,
        max_sentences=20,
    ),
)
result = loop.run()

print(f"Generated {result.num_generated} sentences, coverage: {result.coverage:.1%}")

Generate with an LLM API (Phon-CTG + LLM)

from corpusgen.generate.backends.llm_api import LLMBackend

# Requires: poetry install --with llm
# Set your API key: export OPENAI_API_KEY=...
backend = LLMBackend(
    model="gpt-4o-mini",
    language="en-us",
)

# Use with the same GenerationLoop as above
loop = GenerationLoop(
    backend=backend,
    targets=targets,
    scorer=scorer,
    stopping_criteria=StoppingCriteria(target_coverage=0.9),
)
result = loop.run()

Fine-tune a model with phonetic reward (Phon-RL)

from corpusgen.generate.phon_ctg.targets import PhoneticTargetInventory
from corpusgen.generate.phon_rl.reward import PhoneticReward
from corpusgen.generate.phon_rl.trainer import PhonRLTrainer, TrainingConfig

# Requires: poetry install --with local

# 1. Define targets and reward
targets = PhoneticTargetInventory(
    target_phonemes=["p", "b", "t", "d", "k"],
    unit="phoneme",
)
reward = PhoneticReward(targets=targets, coverage_weight=1.0)

# 2. Configure PPO training
config = TrainingConfig(
    model_name="gpt2",
    num_steps=100,
    learning_rate=1e-5,
    kl_coeff=0.1,
    use_peft=True,     # LoRA for parameter-efficient training
    peft_r=8,
    peft_alpha=16,
    device=None,        # auto-detect GPU
)

# 3. Train with dynamic prompts that adapt to coverage gaps
def make_prompt(targets):
    missing = targets.next_targets(5)
    return f"Write a sentence using these sounds: {', '.join(missing)}"

trainer = PhonRLTrainer(reward=reward, config=config)
result = trainer.train(prompt_fn=make_prompt)

print(f"Final coverage: {result.final_coverage:.1%}")
trainer.save_checkpoint("./phon_rl_checkpoint")

Use PHOIBLE inventories directly

from corpusgen import get_inventory

inv = get_inventory("en-us")
print(inv.language_name)          # 'English'
print(inv.consonants)             # ['p', 'b', 't', 'd', 'k', ...]
print(inv.vowels)                 # ['iː', 'ɪ', 'ɛ', 'æ', ...]

# Query by distinctive features
nasals = inv.segments_with_feature("nasal", "+")
print([s.phoneme for s in nasals])  # ['m', 'n', 'ŋ']

Evaluate with diphone or triphone coverage

import corpusgen

report = corpusgen.evaluate(
    ["The quick brown fox jumps."],
    language="en-us",
    target_phonemes="phoible",
    unit="diphone",
)
print(f"Diphone coverage: {report.coverage:.1%}")

Export reports

import corpusgen

report = corpusgen.evaluate(
    ["The quick brown fox."],
    language="en-us",
    target_phonemes="phoible",
)

# JSON
print(report.to_json(indent=2))

# JSON-LD (linked data)
doc = report.to_jsonld_ex()

# Human-readable at different verbosity levels
from corpusgen.evaluate.report import Verbosity
print(report.render(verbosity=Verbosity.MINIMAL))
print(report.render(verbosity=Verbosity.NORMAL))
print(report.render(verbosity=Verbosity.VERBOSE))

Architecture

corpusgen/
├── g2p/                  # Grapheme-to-phoneme conversion
│   ├── manager.py        # G2PManager — multi-backend G2P (espeak-ng)
│   └── result.py         # G2PResult — phonemes, diphones, triphones
├── coverage/
│   └── tracker.py        # CoverageTracker — phoneme/diphone/triphone tracking
├── evaluate/
│   ├── evaluate.py       # evaluate() — top-level API
│   └── report.py         # EvaluationReport, Verbosity
├── inventory/
│   ├── models.py         # Segment (38 features), Inventory
│   ├── phoible.py        # PhoibleDataset — PHOIBLE loader/cache/query
│   └── mapping.py        # EspeakMapping — espeak ↔ ISO 639-3
├── select/
│   ├── greedy.py         # GreedySelector
│   ├── celf.py           # CELFSelector (lazy evaluation)
│   ├── stochastic.py     # StochasticGreedySelector
│   ├── ilp.py            # ILPSelector (exact, optional: pulp)
│   ├── distribution.py   # DistributionAwareSelector (KL-divergence)
│   └── nsga2.py          # NSGA2Selector (Pareto, optional: pymoo)
├── weights/              # Phoneme weighting strategies
├── generate/
│   ├── phon_ctg/         # Orchestration framework
│   │   ├── targets.py    # PhoneticTargetInventory
│   │   ├── scorer.py     # PhoneticScorer (coverage + phonotactic + fluency)
│   │   ├── constraints.py # PhonotacticConstraint ABC + N-gram model
│   │   └── loop.py       # GenerationLoop + StoppingCriteria
│   ├── phon_rl/          # RL-based guidance (PPO)
│   │   ├── reward.py     # PhoneticReward (composite, hierarchical)
│   │   ├── trainer.py    # PhonRLTrainer (custom PPO, no trl)
│   │   ├── policy.py     # PhonRLStrategy (GuidanceStrategy wrapper)
│   │   └── value_head.py # ValueHead (nn.Module for GAE)
│   ├── phon_datg/        # Inference-time logit steering
│   │   ├── attribute_words.py  # Vocabulary phonemization + index
│   │   ├── modulator.py  # Additive logit modulation
│   │   └── graph.py      # DATGStrategy (GuidanceStrategy)
│   ├── guidance.py       # GuidanceStrategy ABC
│   └── backends/         # Pluggable generation engines
│       ├── repository.py # Sentence pool selection
│       ├── llm_api.py    # Multi-provider LLM API (litellm)
│       └── local.py      # HuggingFace transformers + quantization

Language Support

corpusgen supports any language available in both espeak-ng and PHOIBLE:

• G2P (espeak-ng): 100+ languages
• Inventories (PHOIBLE): 2,186 languages, 3,020 inventories, 8 sources
• Tested across: 40 languages, 12 language families, 10+ scripts

The espeak-to-PHOIBLE mapping covers 85+ languages with automatic macrolanguage resolution (e.g., ms → Standard Malay, sw → Swahili).

Reproducibility

For reproducible results across machines:

1. Pin corpusgen version in your dependency file
2. Pin espeak-ng version: Record espeak-ng --version in experiment logs
3. Use poetry.lock: Pins all transitive dependencies
4. Record PHOIBLE version: Note the download date of ~/.corpusgen/phoible.csv

Citation

If you use corpusgen in your research, please cite:

@software{corpusgen2025,
  title={corpusgen: Language-Agnostic Speech Corpus Generation with Maximal Phoneme Coverage},
  author={Syed, Muntaser},
  year={2025},
  url={https://github.com/jemsbhai/corpusgen}
}

License

Apache 2.0 — see LICENSE.