Classical Mode

English borrowed thousands of nouns from Latin and Greek, and for many of them two plural forms coexist: a modern English form and the original classical form. Plurality defaults to modern English but gives you a clean toggle for classical forms.

Quick start

# Modern defaults (no change needed)
Plurality.pluralize("aquarium")                  #=> "aquariums"
Plurality.pluralize("formula")                   #=> "formulas"
Plurality.pluralize("trauma")                    #=> "traumas"

# Classical mode
Plurality.pluralize("aquarium", classical: true)  #=> "aquaria"
Plurality.pluralize("formula", classical: true)   #=> "formulae"
Plurality.pluralize("trauma", classical: true)    #=> "traumata"

# Words already classical by default are unaffected
Plurality.pluralize("cactus")                     #=> "cacti"
Plurality.pluralize("cactus", classical: true)    #=> "cacti"

# Words without classical forms are unaffected
Plurality.pluralize("leaf", classical: true)      #=> "leaves"

What classical mode changes

Classical mode only affects words that have known Latin/Greek plural forms. Everything else stays the same. There are two levels:

1. Overrides table (69 curated words)

Words where the default is modern but a classical alternative exists. These are stored in priv/data/classical_overrides.tsv and curated from the NIH SPECIALIST Lexicon.

Examples:

2. Suffix rules (for words not in any table)

When classical: true and a word isn't found in the irregulars or overrides tables, Latin/Greek suffix rules apply:

What classical mode does NOT do

Some Latin/Greek patterns have high false positive rates in English. These are never applied as suffix rules, even with classical: true:

If a word ending in -a or -on isn't in the overrides table, it gets normal English pluralization regardless of the classical flag.

Singularization

Singularization is mode-independent. It handles both modern and classical plural forms without needing a flag:

Plurality.singularize("aquariums")  #=> "aquarium"
Plurality.singularize("aquaria")    #=> "aquarium"
Plurality.singularize("traumas")    #=> "trauma"
Plurality.singularize("traumata")   #=> "trauma"
Plurality.singularize("antennae")   #=> "antenna"
Plurality.singularize("antennas")   #=> "antenna"

This works because the reverse lookup map is enriched at compile time with both modern and classical plural forms pointing to the same singular.

Choosing an app default

Plurality does not read application configuration. Keep defaults explicit at the call site, or put the choice behind an application-owned wrapper:

defmodule MyApp.Inflection do
  def pluralize(word, opts \\ []) do
    Plurality.pluralize(word, Keyword.put_new(opts, :classical, true))
  end
end

With inflect/3

The inflect/3 function passes options through to pluralize/2:

Plurality.inflect("aquarium", 2, classical: true)   #=> "aquaria"
Plurality.inflect("aquarium", 1, classical: true)   #=> "aquarium"
Plurality.inflect("formula", 0, classical: true)    #=> "formulae"

With check mode

Classical plurals are recognized by check: true:

Plurality.pluralize("aquaria", check: true)    #=> "aquaria"   (recognized as plural)
Plurality.pluralize("formulae", check: true)   #=> "formulae"  (recognized as plural)

Case preservation

Classical mode preserves input casing:

Plurality.pluralize("Aquarium", classical: true)  #=> "Aquaria"
Plurality.pluralize("FORMULA", classical: true)   #=> "FORMULAE"
Plurality.singularize("ANTENNAE")                 #=> "ANTENNA"

Which words are classical by default?

Some classical forms are so dominant in English that they're the default even without classical: true:

These are in irregulars.tsv with classical plurals as the default. They are NOT in classical_overrides.tsv because no override is needed.

Further reading

See the Methodology guide for detailed documentation of how modern vs. classical decisions were made, the data sources used, and why certain suffix rules are restricted.