Surname::Transliterator

A Ruby gem for cross-language surname transliteration and transformation, based on genealogical rules. Supports transliteration (removing diacritics/Cyrillic) and polonization/de-polonization endings between languages like Polish-Lithuanian, Polish-Russian. Extensible for more pairs. Useful for reducing false positives in genealogical matching.

Features:

• Transliterate surnames (remove diacritics/Cyrillic, handle Polish digraphs like sz/č/cz/rz).
• Transform endings between languages (polonization/de-polonization based on genealogical rules).
• Generate W/V interchange variants for better genealogical matching.
• Support for Polish ↔ Lithuanian, Polish ↔ Russian transformations (asymmetric).

Install the gem and add to the application's Gemfile by executing:

bundle add surname-transliterator

If bundler is not being used to manage dependencies, install the gem by executing:

gem install surname-transliterator

require 'surname/transliterator'

# Convenience methods
polish_to_lith = Surname::Transliterator.polish_to_lithuanian("Łukasiewicz")
# => ["Lukasiewič"] (transliterated with Polish digraphs)

polish_to_lith2 = Surname::Transliterator.polish_to_lithuanian("Antonowicz")
# => ["Antonavičius", "Antonowič"] (transliterated + transformed)

lith_to_polish = Surname::Transliterator.lithuanian_to_polish("Jankauskas")
# => ["Jankowski", "Jankauskas"] (transformed + transliterated)

polish_to_russian = Surname::Transliterator.polish_to_russian("Kowalski")
# => ["Kowalski", "Kowalskii"]

russian_to_polish = Surname::Transliterator.russian_to_polish("Иванов")
# => ["Ivanov"]

# General cross-language normalization (includes W/V interchange for genealogical matching)
variants = Surname::Transliterator.normalize_surname("Wiszniewski", 'polish', 'lithuanian')
# => ["Wišnievskis", "Wišnievskas", "Wišniewski", "Višnievskis", "Višnievskas", "Višniewski"] (transformed + W/V)

# Just transliterate (remove diacritics/Cyrillic)
clean_polish = Surname::Transliterator.transliterate("Świętochowski", 'polish')
# => "Swietochowski"

clean_russian = Surname::Transliterator.transliterate("Иванов", 'russian')
# => "Ivanov"

• Asymmetric Transformations: Translations between languages are not symmetric due to historical genealogical adaptations. For example, Polish -owicz may become Lithuanian -avičius, but reversing it doesn't always restore -owicz exactly. Use polish_to_lithuanian and lithuanian_to_polish as separate methods with their own mappings.

The gem supports transliteration and transformation for the following languages:

• Polish: Full transliteration (diacritics + digraphs like sz/č/cz/rz).
• Lithuanian: Full transliteration.
• Russian: Full transliteration.
• Czech: Basic transliteration (diacritics only, no ending transformations).

Note: Transformations are asymmetric (see below). Add more pairs by editing POLONIZATION_MAPPINGS.

Below is a matrix showing example transformations between languages (not symmetric):

This illustrates why separate methods are needed for each direction.

Edit DIACRITIC_MAPPINGS and POLONIZATION_MAPPINGS in the code to add support for more languages/pairs.

After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/justi/surname-transliterator.