haqumei 0.2.5 - Docs.rs

Features

Phoneme <-> Word mapping: Provides phoneme-to-word alignment by linking morphological analysis results with phonemes (g2p_pairs, g2p_mapping, g2p_mapping_detailed).
This capability is not available in Open JTalk or pyopenjtalk. (See Advanced Features)
Performance: Enables fast G2P through a native Rust implementation and by incorporating several improvements from pyopenjtalk-plus. (See Benchmark)
Output Formats: Provides results in various formats, including a simple phoneme sequence (g2p), a detailed list including unknown word information (g2p_detailed), and a list split by words (g2p_per_word).
Concurrency: Enables concurrent G2P processing across multiple threads using the *_batch methods.

Examples can be found in haqumei/examples.

Install

Rust

During the initial build of haqumei, the dictionary is downloaded and embedded into the binary due to the file size limits on crates.io. For custom dictionaries, or for environments where network access is unavailable during the build, please refer to here.

cargo add haqumei

Python

pip install "git+https://github.com/stellanomia/haqumei.git#subdirectory=haqumei-python"

Usage

Rust

use haqumei::Haqumei;

fn main() -> Result<(), Box<dyn std::error::Error>> {
  let mut haqumei = Haqumei::new()?;

  let text = "日本語のテキストを音素に変換します。";

  // Convert to a list of phonemes
  let phonemes = haqumei.g2p(text)?;
  println!("Phoneme list: {:?}", phonemes);

  // Convert to a space-separated string like pyopenjtalk
  let phoneme_str = phonemes.join(" ");
  println!("Space-separated phonemes: {}", phoneme_str);

  // Convert to Katakana reading
  let kana = haqumei.g2p_kana(text)?;
  println!("Katakana reading: {}", kana);

  Ok(())
}

Python

from haqumei import Haqumei

# Initialize Haqumei (the dictionary will be automatically set up)
haqumei = Haqumei()

text = "日本語のテキストを音素に変換します。"

# Convert to a phoneme list
phonemes = haqumei.g2p(text)
print(f"Phoneme list: {phonemes}")
# -> Phoneme list: ['n', 'i', 'h', 'o', 'N', 'g', 'o', 'n', 'o', 't', 'e', 'k', 'i', 's', 'U', 't', 'o', 'o', 'o', 'N', 's', 'o', 'n', 'i', 'h', 'e', 'N', 'k', 'a', 'N', 'sh', 'i', 'm', 'a', 's', 'U']

# Convert to a space-separated string like pyopenjtalk
phoneme_str = " ".join(phonemes)
print(f"Space-separated phonemes: {phoneme_str}")
# -> Space-separated phonemes: n i h o N g o n o t e k i s U t o o o N s o n i h e N k a N sh i m a s U

# Convert to Katakana reading
kana = haqumei.g2p_kana(text)
print(f"Katakana reading: {kana}")
# -> Katakana reading: ニホンゴノテキストヲオンソニヘンカンシマス

Advanced Features

Getting Phoneme Mapping with the Original Word String

Haqumei implements g2p_pairs to obtain the correspondence between phonemes and their original words.
This is achieved by traversing the JPCommon structure and tracking the pointers to the words to which each phoneme belongs.

use haqumei::Haqumei;

fn main() -> Result<(), Box<dyn std::error::Error>> {
  let mut haqumei = Haqumei::new()?;

  println!("{:?}", haqumei.g2p_pairs("𰻞𰻞麺＆お冷を頼んだ")?);
  // [WordPhonemePair {
  //     word: "𰻞𰻞",
  //     phonemes: ["pau"]
  // }, WordPhonemePair {
  //     word: "麺",
  //     phonemes: ["m", "e", "N"]
  // }, WordPhonemePair {
  //     word: "＆",
  //     phonemes: ["a", "N", "d", "o"]
  // }, WordPhonemePair {
  //     word: "お冷",
  //     phonemes: ["o", "h", "i", "y", "a"]
  // }, ... ]
}

Detailed G2P Output

In Open JTalk (pyopenjtalk), unknown words are treated as pau (pauses), and Haqumei's standard g2p function follows this behavior.
However, by using the g2p_**_detailed functions, you can detect otherwise ignored unknown words and spaces as unk and sp respectively.

Please note that sp does not refer to raw space characters in the input, but rather the "記号,空白" (symbol, space) part-of-speech output by Mecab, which is normally ignored in pyopenjtalk. Therefore, symbols that Mecab itself ignores (e.g., \t, \n) are not included in sp.

Known words: Regular phoneme sequence (punctuation marks become pau).
Unknown words: unk
Spaces, etc.: sp (Space)

Using g2p_mapping, you can obtain the phoneme-to-word mapping along with flags indicating whether a word is unknown (is_unknown) and whether it would normally be ignored in the original pipeline (is_ignored). In addition, using g2p_mapping_detailed allows you to retrieve not only the mapping but also part-of-speech information and accent details.

use haqumei::Haqumei;

fn main() -> Result<(), Box<dyn std::error::Error>> {
  let mut haqumei = Haqumei::new()?;

  println!("{:?}", haqumei.g2p_detailed("こんにちは 𰻞𰻞麺")?);
  // ["k", "o", "N", "n", "i", "ch", "i", "w", "a", "sp", "unk", "m", "e", "N"]

  println!("{:?}", haqumei.g2p_mapping("𰻞𰻞麺 お冷を頼んだ")?);
  // [WordPhonemeMap {
  //     word: "𰻞𰻞",
  //     phonemes: ["unk"],
  //     is_unknown: true,
  //     is_ignored: false,
  // },
  // WordPhonemeMap {
  //     word: "麺",
  //     phonemes: ["m", "e", "N"],
  //     is_unknown: false,
  //     is_ignored: false,
  // },
  // WordPhonemeMap {
  //     word: "\u{3000}",
  //     phonemes: ["sp"],
  //     is_unknown: false,
  //     is_ignored: true,
  // },
  // WordPhonemeMap {
  //     word: "お冷",
  //     phonemes: ["o", "h", "i", "y", "a"],
  //     is_unknown: false,
  //     is_ignored: false,
  // }, ... ]

  println!("{:?}", haqumei.g2p_mapping_detailed("薄明")?);
  // [WordPhonemeDetail {
  //    word: "薄明",
  //    phonemes: ["h","a","k","u","m","e","e"],
  //    features: [
  //        "薄明",
  //        "名詞",
  //        "一般",
  //        "*",
  //        "*",
  //        "*",
  //        "*",
  //        "薄明",
  //        "ハクメイ",
  //        "ハクメー",
  //        "0/4",
  //        "C2",
  //    ],
  //    pos: "名詞",
  //    pos_group1: "一般",
  //    pos_group2: "*",
  //    pos_group3: "*",
  //    ctype: "*",
  //    cform: "*",
  //    orig: "薄明",
  //    read: "ハクメイ",
  //    pron: "ハクメー",
  //    accent_nucleus: 0,
  //    mora_count: 4,
  //    chain_rule: "C2",
  //    chain_flag: -1,
  //    is_unknown: false,
  //    is_ignored: false,
  // }]
}

Modifying Output with G2P Options

You can customize the behavior of Haqumei by using Haqumei::with_options. For details on the default behavior and available options, please refer to HaqumeiOptions.

In the following example, normalize_unicode (which is disabled by default) is enabled to apply Unicode NFC normalization to the input text.

use haqumei::{Haqumei, HaqumeiOptions, UnicodeNormalization};

fn main() -> Result<(), Box<dyn std::error::Error>> {
  let mut haqumei = Haqumei::with_options(HaqumeiOptions {
    normalize_unicode: UnicodeNormalization::Nfc,
    ..Default::default()
  })?;

  let text = &[
    "\u{304B}\u{3099}", // か + ゙ (が)
    "\u{306F}\u{309A}", // は + ゚ (ぱ)
    "\u{30B3}\u{3099}", // コ + ゙ (ゴ)
  ];

  println!("{:?}", haqumei.g2p_detailed_batch(text)?);
  // Output: [["g", "a"], ["p", "a"], ["g", "o"]]
}

Benchmark

Here are the comparison results between pyopenjtalk (Baseline) and haqumei using approximately 318,000 characters of Japanese text.

Input data: I Am a Cat (吾輩は猫である) 318,407 chars / 8,451 lines (Average 37 chars/line) (Ruby characters have been removed)

Execution Mode	Execution Time (Mean)	Throughput	Speedup
pyopenjtalk (Baseline)	2.358 s	135k chars/s	1.00x
haqumei (Default)	1.303 s	244k chars/s	1.81x
haqumei (`g2p_batch`, Default)	0.098 s	3.24M chars/s	24.04x
haqumei (Heavy)	2.101 s	151k chars/s	1.12x
haqumei (`g2p_batch`, Heavy)	0.268 s	1.18M chars/s	8.80x

The detailed benchmark code can be found in haqumei-bench/pyopenjtalk.

Additionally, Rust-layer benchmarks for Haqumei using Criterion.rs can be run via cargo bench in the haqumei-bench crate. The comparison benchmark with pyopenjtalk-plus is located in haqumei-bench/pyopenjtalk-plus.

Performance Notes

Throughput Variation by Input Structure:
Especially in the *_batch APIs, throughput (chars/s) tends to increase as the number of characters per line grows (up to approximately 4KB), compared with pyopenjtalk. This efficiency stems from an implementation that directly extracts labels from Open JTalk's internal structures, combined with minimal FFI overhead. When processing large volumes of text, it is most efficient to pass content in substantial chunks rather than splitting it into excessively short lines.
Difference Between Default and Heavy:
In the table, "Default" represents the configuration using Haqumei::new as is, while "Heavy" shows the results when predict_nani and modify_kanji_yomi are enabled in HaqumeiOptions.

Building with a Custom Embedded Dictionary

By default, haqumei downloads the dictionary at build time and embeds it into the binary. This allows the crate to be published to crates.io while still producing a self-contained binary.

If you want to build with your own dictionary embedded in the binary, you can change the configuration as follows.

Change the Cargo Features

Disable the default download-dictionary feature and enable build-dictionary.

[dependencies]
haqumei = { version = "x.y.z", features = ["embed-dictionary", "build-dictionary"], default-features = false }

Prepare the Dictionary Source and Set the Environment Variable

Prepare a dictionary source directory containing .csv and .def files to be compiled at build time, then set its path to the HAQUMEI_DICT_SRC environment variable before running the build.

On Unix-like systems:

HAQUMEI_DICT_SRC="/path/to/your/dictionary" cargo build --release

On Windows (PowerShell):

& { $env:HAQUMEI_DICT_SRC="C:\path\to\your\dictionary"; cargo build --release }

Note: If the environment variable is not set, the build script falls back to dictionary, relative to the crate root.

Dictionary

Haqumei uses the dictionary included in pyopenjtalk-plus.

License

The Rust code of haqumei is distributed under the terms of the Apache License 2.0. See the LICENSE file in the repository root for details.

Licenses and Origins of Bundled Software

haqumei includes C/C++ source code from a modified version of Open JTalk to provide its Grapheme-to-Phoneme (G2P) functionality. The origins and licenses of this bundled code are as follows:

Bundled Open JTalk Source Code
- Origin: The code contained in the vendor/open_jtalk directory is based on the tsukumijima/open_jtalk repository, which integrates improvements from various community forks (including those from the VOICEVOX project) into an enhanced version of Open JTalk.
- License: The bundled Open JTalk source code is licensed under the Modified BSD License. This license applies only to the code located in vendor/open_jtalk, and does not apply to the rest of this project. In accordance with redistribution requirements, the full text of the Modified BSD License is included in vendor/open_jtalk/src/COPYING.

Acknowledgements

The overall design and API of haqumei are inspired by pyopenjtalk and its highly improved fork, pyopenjtalk-plus.

We are deeply grateful to the authors and contributors of these foundational projects.