Lang::JA::Kana::Romaji

Documentation:

• Main: English • 日本語

• Romaji: README-Romaji.md

• Cyrillic: English • Русский

• Hangul: English • 한국어

ローマ字 - Japanese Kana to Romaji Transliteration Module

A comprehensive Raku module for converting Japanese Kana (Hiragana and Katakana) to Romaji using the three major standardized romanization systems, each designed for different purposes and linguistic requirements.

Table of Contents

• Features

• Installation

• Quick Start

• Romanization Systems

• Usage Examples

• System Comparisons

• Advanced Features

• API Reference

• Character Coverage

• Linguistic Notes

• Testing

• Contributing

• License

Features

• 4 Romanization Systems with distinct linguistic approaches

• Traditional Hepburn (default) - Most common, pronunciation-based

• Modified Hepburn - Academic standard with macrons for long vowels

• Kunrei-shiki - ISO 3602 standard, systematic approach

• Nihon-shiki - Preserves Japanese phonological distinctions

• Sokuon (っ) Processing with consonant doubling

• Long Vowel Handling with macron notation (Modified Hepburn)

• Modern Extensions (ファ, ティ, ヴ sounds)

• Historical Kana Support (ゐゑを)

• Mixed Content Handling (non-kana passed through unchanged)

Installation

# Install from ecosystem
zef install Lang::JA::Kana

# Or clone and install locally
git clone https://github.com/your-repo/lang-ja-kana.git
cd lang-ja-kana
zef install .

Quick Start

use Lang::JA::Kana::Romaji;

# Basic usage (Traditional Hepburn - default)
say romaji("こんにちは");           # konnichiha
say romaji("しんぶん");             # shinbun
say romaji("じゃじゅじょ");         # jajujo

# Different systems
say romaji("しんぶん", :system<kunrei>);      # sinbun
say romaji("ふじさん", :system<kunrei>);      # huzisan
say romaji("づつき", :system<nihon>);         # dutuki

# Modified Hepburn with macrons
say romaji("とうきょう", :system<hepburn-mod>); # tōkyō
say romaji("ラーメン", :system<hepburn-mod>);   # rāmen

Romanization Systems

Traditional Hepburn (Default)

Modified Hepburn

Kunrei-shiki (Cabinet Order)

Nihon-shiki (Japanese Style)

Usage Examples

Basic Conversion

use Lang::JA::Kana::Romaji;

# Hiragana
say romaji("ひらがな");        # hiragana

# Katakana  
say romaji("カタカナ");        # katakana

# Mixed text (non-kana passed through)
say romaji("Hello こんにちは World");  # Hello konnichiha World

System Comparisons

my $word = "しんぶん";

say "Traditional: " ~ romaji($word);                    # shinbun
say "Kunrei:      " ~ romaji($word, :system<kunrei>);   # sinbun
say "Nihon:       " ~ romaji($word, :system<nihon>);    # sinbun

my $word2 = "じゃじゅじょ";
say "Traditional: " ~ romaji($word2);                   # jajujo
say "Kunrei:      " ~ romaji($word2, :system<kunrei>);  # zyazyuzyo
say "Nihon:       " ~ romaji($word2, :system<nihon>);   # zyazyuzyo

Long Vowels

# Traditional Hepburn - double letters
say romaji("がっこう");                        # gakkou
say romaji("とうきょう");                      # toukyou

# Modified Hepburn - macrons
say romaji("がっこう", :system<hepburn-mod>);   # gakkō
say romaji("とうきょう", :system<hepburn-mod>);  # tōkyō
say romaji("ラーメン", :system<hepburn-mod>);    # rāmen

Phonological Distinctions

# Nihon-shiki preserves ぢ/づ vs じ/ず distinctions
say romaji("づつき", :system<nihon>);     # dutuki
say romaji("じずく", :system<nihon>);     # zizuku

# Other systems merge them
say romaji("づつき", :system<kunrei>);    # dutuki (same as nihon for this)
say romaji("づつき");                     # zutsuki (traditional hepburn)

Modern Extensions

# Foreign sound adaptations
say romaji("ファイル");          # fairu
say romaji("ティーム");          # timu
say romaji("ヴァイオリン");      # vaiorin
say romaji("ウィンドウ");        # windou
say romaji("チェック");          # chekku

Historical Kana

# Pre-war kana
say romaji("ゐゑを");       # wiwewo
say romaji("ゔぁゔぃ");     # vavi

# All systems handle these consistently
say romaji("ゐゑを", :system<kunrei>);   # wiwewo
say romaji("ゐゑを", :system<nihon>);    # wiwewo

System Comparisons

Key Differences Table

Use Case Recommendations

Traditional Hepburn - Choose when:

• Creating content for general audiences

• Making signs, menus, tourist materials

• Prioritizing pronunciation similarity to English

• Working with non-academic applications

Modified Hepburn - Choose when:

• Writing academic or scholarly works

• Creating dictionaries or reference materials

• Need precise long vowel notation

• Following academic publishing standards

Kunrei-shiki - Choose when:

• Following ISO standards

• Creating systematic educational materials

• Working with Japanese government documents

• Need consistent, regular mapping

Nihon-shiki - Choose when:

• Studying historical Japanese linguistics

• Preserving phonological distinctions

• Analyzing classical Japanese texts

• Working with etymological research

Advanced Features

Sokuon (っ) Handling

The module properly handles small tsu (っ/ッ) by doubling the following consonant:

say romaji("がっこう");     # gakkou (doubled k)
say romaji("ちょっと");     # chotto (doubled t)
say romaji("いっぱい");     # ippai (doubled p)
say romaji("あっさり");     # assari (doubled s)

Long Vowel Processing

Different systems handle long vowels differently:

# Traditional Hepburn - literal transcription
say romaji("おおきい");     # ookii
say romaji("とうきょう");   # toukyou

# Modified Hepburn - macron notation
say romaji("おおきい", :system<hepburn-mod>);   # ookī
say romaji("とうきょう", :system<hepburn-mod>); # tōkyō

# ー (chōonpu) extension
say romaji("ラーメン", :system<hepburn-mod>);   # rāmen
say romaji("コーヒー", :system<hepburn-mod>);   # kōhī

Modern Sound Extensions

# ファ行 (fa-gyō) sounds
say romaji("ファミリー");    # famirii
say romaji("フィルム");      # firumu
say romaji("フェスタ");      # fesuta
say romaji("フォルダ");      # foruda

# ティ/ディ sounds
say romaji("ティーポット");  # tiipotto
say romaji("ディスク");      # disuku

# ヴ sounds (v-sounds)
say romaji("ヴァイオリン");  # vaiorin
say romaji("ヴィーナス");    # viinasu

# ツァ行 sounds
say romaji("ツァイト");      # tsaito
say romaji("ツィター");      # tsitaa

Mixed Content Handling

Non-kana characters pass through unchanged:

say romaji("彼はにほんじんです");       # 彼hanihonzindesu
say romaji("Email: [email protected]"); # Email: [email protected]
say romaji("価格：せんえん");          # 価格：senen
say romaji("123 あいう ABC");          # 123 aiuuu ABC

API Reference

Main Function

sub romaji(Str $text, Str :$system = 'hepburn') is export

Parameters:

• $text - Input text containing Japanese kana

• :$system - Romanization system (optional, default: 'hepburn')

Valid Systems:

• 'hepburn' | 'hep' - Traditional Hepburn (default)

• 'hepburn-mod' | 'hepburn-modified' | 'modified-hepburn' - Modified Hepburn

• 'kunrei' | 'kunrei-shiki' - Kunrei-shiki

• 'nihon' | 'nihon-shiki' - Nihon-shiki

Returns: String with kana converted to romaji

Example:

my $result = romaji("こんにちは", :system<kunrei>);

Error Handling

Unknown systems will cause the function to die with an error message:

# This will die
romaji("test", :system<unknown>);
# Unknown romanization system: unknown. Use 'hepburn', 'hepburn-mod', 'kunrei', or 'nihon'.

Integration with Main Module

This module is part of the larger Lang::JA::Kana package:

use Lang::JA::Kana;

# Direct access via main module
say kana-to-romaji("こんにちは");
say kana-to-romaji("さくら", :system<kunrei>);

# Or use submodule directly
use Lang::JA::Kana::Romaji;
say romaji("こんにちは");

Character Coverage

Supported Kana

Hiragana: All standard hiragana including:

• Basic syllabary (あ-ん)

• Voiced marks (が-ぽ)

• Combinations (きゃ-ぴょ)

• Small variants (ぁ-ゎ)

• Historical forms (ゐゑ)

• Modern extensions (ふぁ-ゔぉ)

Katakana: Complete katakana coverage including:

• Basic syllabary (ア-ン)

• Voiced marks (ガ-ポ)

• Combinations (キャ-ピョ)

• Small variants (ァ-ヮ)

• Modern extensions (ファ-ヴォ)

Unsupported Content

• Kanji: Passed through unchanged

• Latin alphabet: Passed through unchanged

• Numbers: Passed through unchanged

• Punctuation: Passed through unchanged

• Half-width katakana: Must be converted to full-width first

Linguistic Notes

System Design Philosophy

Each romanization system reflects different priorities:

• Traditional Hepburn prioritizes intuitive pronunciation for English speakers

• Modified Hepburn adds academic precision with macron notation

• Kunrei-shiki emphasizes systematic consistency and regularity

• Nihon-shiki preserves all Japanese phonological distinctions

Historical Context

Traditional Hepburn (1867):

• Created by James Curtis Hepburn for his Japanese-English dictionary

• Designed for English speakers learning Japanese

• Most widely used in general contexts

Modified Hepburn (1954):

• Standardized by the American National Standards Institute

• Adds macrons for accurate long vowel representation

• Standard in academic and reference works

Kunrei-shiki (1954):

• Official Japanese government standard

• Based on Japanese phonological structure

• ISO 3602 international standard

Nihon-shiki (1885):

• Oldest systematic romanization

• Created by Tanakadate Aikitsu

• Preserves historical phonological distinctions

Phonological Considerations

Sokuon (っ) Handling:

• Represents a moraic consonant in Japanese

• Realized as consonant doubling or glottal stop

• All systems double the following consonant

Long Vowel Representation:

• Traditional: Literal (ou, uu, etc.)

• Modified: Macrons (ō, ū, etc.)

• Reflects different notation philosophies

ぢ/づ vs じ/ず Distinction:

• Modern Japanese: Pronounced identically

• Historical: Different sounds

• Nihon-shiki preserves the distinction

Testing

The module includes comprehensive tests:

# Run basic tests
raku t/01-basic.t

# Test specific systems
raku -Ilib -e 'use Lang::JA::Kana::Romaji; say romaji("test-input", :system<system-name>)'

Performance Considerations

• Character conversion uses hash lookups (O(1) per character)

• Multi-character combinations are processed longest-first

• Memory usage scales with input text length

• System selection has minimal overhead

Examples Gallery

Literature Translation

my $haiku = "ふるいけや\nかえるとびこむ\nみずのおと";

say "Traditional: " ~ romaji($haiku);
# huruikeya
# kaerutobiko mu
# mizunooto

say "Modified: " ~ romaji($haiku, :system<hepburn-mod>);
# huruikeya
# kaerutobiko mu
# mizunooto (same for this example)

Place Names

say romaji("とうきょう");      # toukyou
say romaji("おおさか");        # oosaka
say romaji("ひろしま");        # hiroshima
say romaji("きょうと");        # kyouto

# With macrons
say romaji("とうきょう", :system<hepburn-mod>);  # tōkyō
say romaji("おおさか", :system<hepburn-mod>);    # ōsaka

Technical Terms

say romaji("コンピューター");   # konpyuutaa
say romaji("インターネット");   # intaanetto
say romaji("テクノロジー");     # tekunorojii
say romaji("ソフトウェア");     # sofutowea

Food and Culture

say romaji("すし");         # sushi
say romaji("らーめん");     # raamen
say romaji("てんぷら");     # tenpura
say romaji("からおけ");     # karaoke
say romaji("おりがみ");     # origami

Contributing

Contributions are welcome. Please visit the project repository at:https://github.com/slavenskoj/raku-lang-ja-kana

We apologize for any errors and welcome suggestions for improvements.

License

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.

See Also

• Lang::JA::Kana - Main module documentation

• Lang::JA::Kana::Kuriru-moji - Cyrillic transliteration

• Lang::JA::Kana::Hangul - Hangul transliteration

• ISO 3602 - Kunrei-shiki standard

• ANSI Z39.11-1972 - Modified Hepburn standard

Authors

Danslav Slavenskoj

ローマ字モジュール - bridging Japanese and Latin scripts with linguistic precision and academic rigor.