shabda

shabda (Sanskrit: word / sound) — Grapheme-to-phoneme (G2P) conversion for Rust.

The bridge between text and vocal synthesis. Converts English text to phoneme sequences ready for svara's synthesis engine. Uses shabdakosh's 10,000+ entry pronunciation dictionary with intelligent rule-based fallback.

Features

• G2P engine: Text to phoneme events in one call
• 10,000+ word dictionary: Via shabdakosh — CMUdict-derived, O(1) lookup, variant pronunciations
• Rule-based fallback: Context-sensitive letter-to-sound rules for unknown words
• Silent letter handling: knight, gnome, write, psychology, lamb, etc.
• Morphological awareness: -tion/-sion suffixes, -ed endings (/t/ vs /d/ vs /ɪd/), un-/re-/dis- prefixes
• Magic-e and r-colored vowels: make→/meɪk/, car→/kɑr/, bird→/bɜrd/
• Syllabification: Maximal Onset Principle with sonority constraints
• Syllable-weight stress: Heavy penult rule for polysyllabic words
• Phrase-level prosody: Commas insert 150ms pauses, periods insert 300ms pauses
• Number expansion: 42→"forty two", 3.14→"three point one four"
• speak() method: Text to audio samples in one call (G2P + svara rendering)
• Custom dictionaries: Add application-specific pronunciations via user overlay
• Serde support: All types serialize/deserialize
• no_std compatible: Works with alloc, no standard library required

Quick Start

use shabda::prelude::*;

// Convert text to phonemes
let g2p = G2PEngine::new(Language::English);
let events = g2p.convert("hello world").unwrap();

// Or go directly to audio
let voice = svara::voice::VoiceProfile::new_male();
let samples = g2p.speak("hello world", &voice, 44100.0).unwrap();

Architecture

Input text
    |
    v
Number Expansion (42 → "forty two")
    |
    v
Normalizer (lowercase, punctuation → phrase markers)
    |
    v
Tokenizer (split into words, detect phrase boundaries)
    |
    v
G2P Engine (dictionary lookup → rule-based fallback)
    |  Rules: silent letters → prefix strip → pattern match → suffix post-process
    v
Syllabifier (Maximal Onset Principle)
    |
    v
Prosody Mapper (syllable-weight stress, phrase pauses)
    |
    v
Vec<PhonemeEvent> (ready for svara)

Feature Flags

Consumers

• dhvani — AGNOS audio engine (text-to-speech pipeline)
• vansh — Voice AI shell
• Any application needing text-to-speech with svara

License

GPL-3.0-only