Custom Pronunciation

Overview

FluidAudio TTS supports custom pronunciation dictionaries that override how specific words are pronounced. Essential for domain-specific terminology, brand names, acronyms, and proper nouns.

Priority Order

Per-word phonetic overrides — Inline markup like [word](/phonemes/)
Custom lexicon — Your word=phonemes file entries
Case-sensitive built-in lexicon
Standard built-in lexicon
Grapheme-to-phoneme (G2P) — eSpeak-NG fallback

File Format

# This is a comment
kokoro=kəkˈɔɹO
NASDAQ=nˈæzdæk
UN=junˈaɪtᵻd nˈeɪʃənz

Phonemes are compact IPA strings. Use whitespace to separate words in multi-word expansions.

Word Matching

Three-tier strategy:

Exact match — NASDAQ matches only NASDAQ
Case-insensitive — nasdaq matches NASDAQ, Nasdaq
Normalized — Strips to letters/digits/apostrophes, lowercased

Usage

CLI

swift run fluidaudio tts "The NASDAQ index rose today" \
  --lexicon custom.txt --output output.wav

Swift API

let lexicon = try TtsCustomLexicon.load(from: fileURL)

let manager = TtSManager(customLexicon: lexicon)
try await manager.initialize()
let audio = try await manager.synthesize(text: "Welcome to Kokoro TTS")

// Update at runtime
manager.setCustomLexicon(newLexicon)

Merging Lexicons

let combined = baseLexicon.merged(with: domainLexicon)

Example Lexicon

# Finance
NASDAQ=nˈæzdæk
EBITDA=iːbˈɪtdɑː

# Technology
NVIDIA=ɛnvˈɪdiə
Kubernetes=kuːbɚnˈɛtiːz

# Product Names
Kokoro=kəkˈɔɹO
FluidAudio=flˈuːɪd ˈɔːdioʊ

Getting Started

Speech Recognition (ASR)

Speaker Diarization

Voice Activity Detection

Text-to-Speech (TTS)

Guides

Reference

Overview

Priority Order

File Format

Word Matching

Usage

CLI

Swift API

Merging Lexicons

Example Lexicon

​Overview

​Priority Order

​File Format

​Word Matching

​Usage

​CLI

​Swift API

​Merging Lexicons

​Example Lexicon

Overview

Priority Order

File Format

Word Matching

Usage

CLI

Swift API

Merging Lexicons

Example Lexicon