---
id: cmudict
version: "1.1.3"
license: GPL-3.0-or-later
license_treatment: copyleft
maintenance: active
---

# cmudict — A versioned python wrapper package for The CMU Pronouncing Dictionary data files.

License: copyleft · Maintenance: active · Downloads: 359.3K/mo

## What it is and what it does

cmudict is a thin Python wrapper around The CMU Pronouncing Dictionary, a linguistic dataset of English word pronunciations in phonetic notation. It bundles the dictionary data files and exposes them through a simple API with three access patterns per file: raw string, binary stream, or minimally-processed Python structures. The package maintains compatibility with NLTK's cmudict interface, making it a drop-in alternative for projects already using that corpus reader.

The main use case is looking up how words are pronounced or extracting phonetic information for speech synthesis, voice recognition, poetry analysis, or linguistic research. It requires Python 3.9+ and has minimal dependencies—only two standard-library backports—making it straightforward to install and integrate into existing projects.

Use it for:

- Look up phonetic transcriptions of English words for speech synthesis or pronunciation guides.
- Extract phone inventories and phonetic symbols for linguistic analysis or NLP feature engineering.
- Build rhyming or alliteration detection tools by comparing phonetic representations.
- Migrate from NLTK's cmudict reader to a standalone, versioned dictionary package.
- Analyze poetry or song lyrics for phonetic patterns and stress patterns.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides Python access to the CMU Pronouncing Dictionary data files (phonetic transcriptions, phone inventories, and related linguistic data) with minimal processing and NLTK compatibility.

Yes, if you need English phonetic data. Low install friction, no security issues, active maintenance, and GPL-3.0-or-later licensing is straightforward for open-source projects. Not suitable for proprietary software without GPL compliance review. The NLTK compatibility makes it a practical choice for speech and linguistic work.

## Install

pip install cmudict
uv add cmudict
poetry add cmudict

## Installing cmudict

Before you install: Low friction: pure Python wheel with only two standard-library backport dependencies (importlib-metadata, importlib-resources). Actively maintained with recent commits and stable production status.

License in practice: GPL-3.0-or-later (copyleft): any derivative work or software that links this package must be distributed under the same or compatible GPL license; proprietary or closed-source projects cannot use it without legal review.

Quickstart:

pip install cmudict

import cmudict

# Access phonetic dictionary (NLTK-compatible)
dict_data = cmudict.dict()

# Or get raw string contents
dict_str = cmudict.dict_string()

Requires Python 3.9 or later (supports up to 3.14).

Verify before relying:

- Size and memory footprint of the bundled CMU dictionary data files when loaded into memory.
- Performance characteristics when querying large phonetic datasets or iterating over all entries.

## Package facts

- License: GPL-3.0-or-later (copyleft)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 359.3K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

cmu pronouncing dictionary python, phonetic transcription lookup, word pronunciation data, linguistic dictionary api, cmudict wrapper, nltk cmudict compatible, phonetics, linguistics, nlp

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