@jocelyn-stericker/espeak-phonemes (0.0.6)
Installation
@jocelyn-stericker:registry=npm install @jocelyn-stericker/espeak-phonemes@0.0.6"@jocelyn-stericker/espeak-phonemes": "0.0.6"About this package
espeak-phonemes
English text → IPA phonemes, using a size-optimized WebAssembly build of eSpeak NG. Works in Node.js and browsers, offline, with no audio-synthesis code shipped.
import { textToIPA } from "@jocelyn-stericker/espeak-phonemes";
const ipa = await textToIPA("Hello world");
// → "həlˈəʊ wˈɜːld"
This repo is not a fork of eSpeak NG. It pins upstream as a git submodule,
applies a small patch (patches/espeak-ng-phonemes.patch) that trims the build
to translation-only and adds a phonemes-only data mode, then cross-compiles a
~300 KB WASM module plus English data that compresses to ~120 KB over the wire. See
Build and PORT_PLAN.md.
Install
This package is published to a Forgejo (Codeberg) npm registry. Add the scope to
your project's .npmrc:
@jocelyn-stericker:registry=https://codeberg.org/api/packages/jocelyn-stericker/npm/
Then install a pinned version (builds are not guaranteed compatible across versions):
npm install --save-exact @jocelyn-stericker/espeak-phonemes
Usage
Node.js (auto-resolves the bundled assets)
import { textToIPA } from "@jocelyn-stericker/espeak-phonemes";
await textToIPA("hello"); // "həlˈəʊ"
await textToIPA("hello", { voice: "en-us" }); // "həlˈoʊ"
await textToIPA("hello", { keepStress: false }); // "hələʊ"
Browser (supply the assets explicitly)
The Node convenience wrapper resolves files from disk; in the browser use the
low-level createESpeak and hand it the emscripten factory + data archive. With
a bundler like Vite, the ?url suffix yields the served asset URL:
import { createESpeak } from "@jocelyn-stericker/espeak-phonemes";
import initWasm from "@jocelyn-stericker/espeak-phonemes/espeak-phonemes.js";
import wasmUrl from "@jocelyn-stericker/espeak-phonemes/espeak-phonemes.wasm?url";
import dataUrl from "@jocelyn-stericker/espeak-phonemes/espeak-ng-data.tar?url";
const resp = await fetch(dataUrl);
const engine = await createESpeak({
moduleFactory: initWasm,
moduleOverrides: { locateFile: () => wasmUrl }, // so the glue finds the .wasm
data: { archive: await resp.arrayBuffer() }, // raw tar; omit `compression`
});
engine.textToIPA("Hello from the browser!"); // synchronous after init
Options
| Option | Type | Default | Description |
|---|---|---|---|
voice |
"en" | "en-us" |
"en" |
English voice variant |
separator |
string |
" " |
String between phoneme groups (words + clauses) |
keepStress |
boolean |
true |
Keep ˈˌ stress marks |
tie |
string |
— | Tie character inserted within multi-char phonemes (e.g. "͡" → ə͡ʊ) |
Differences from the espeak-ng CLI
Output matches espeak-ng -q --ipa -v en except for one case: the CLI's
intonation pass (part of audio synthesis, which this build omits) adds an
emphasis mark to a lone single-syllable function word — the → ðˈə,
is → ˈɪz. This build emits the unstressed lexical form (ðə, ɪz). Lexical
stress on content words and stress within running text are unaffected.
Build
The whole pipeline lives in scripts/ and runs on push via
.forgejo/workflows/ci.yaml (the version bumps every run).
git clone --recurse-submodules <this repo>
cd espeak-phonemes
npm install
source "$EMSDK/emsdk_env.sh" # an activated Emscripten SDK
npm run build # patch → native data → wasm → TypeScript
npm run test:golden # parity vs the captured CLI corpus
scripts/build.sh orchestrates:
scripts/apply-patch.sh— overlayspatches/espeak-ng-phonemes.patchonto the pinnedespeak-ng/submodule (idempotent).- A native build to compile the phonemes-only English data
(
ESPEAK_PHONEMES_ONLY=1; the data compiler runs on the host). scripts/build-wasm.sh— emscripten build of the translation-only library, emittingespeak-phonemes.{wasm,js}andespeak-ng-data.tar.tsc— compiles the TypeScript wrapper todist/esm/.
Bumping upstream eSpeak NG
git -C espeak-ng fetch && git -C espeak-ng checkout <new-sha>
git -C espeak-ng apply ../patches/espeak-ng-phonemes.patch # re-roll if it fails
git add espeak-ng
npm run build && npm run test:golden # the corpus is the safety net
If the patch no longer applies after an upstream refactor, re-create it against
the new tree and commit the updated patches/espeak-ng-phonemes.patch. The
golden corpus (tests/golden-corpus.ndjson) is the oracle that confirms a bump
didn't change pronunciations.
License
AGPL-3.0-or-later
A derivative of eSpeak NG (GPLv3).
Copyright (C) 2006–2024 Jonathan Duddington and contributors. The bundled
espeak-ng-data.tar and the WASM binary are built from eSpeak NG source.
Dependencies
Development dependencies
| ID | Version |
|---|---|
| @types/node | ^25.9.1 |
| typescript | ^6.0.3 |