Introduction

Morphology is the means by which a surface string is converted its canonical form, and the reverse: how a canonical form is converted to a surface form. For example, noun morphology lets us turn the plural form "dogs" into the canonical form "dog" and the reverse. Verb morphology allows us to convert the gerund form "sleeping" into the canonical form "sleep" as well as the reverse conversion.

Notation

We'll use EDN as the format for morphological rules. For example, see menard/english/nouns.edn. One such rule is:

{:g [#"(.*)$"   "$1s"]  ;; dog     -> dogs
 :p [#"(.*)s$"  "$1"]  ;;  dogs    -> dog
 :agr {:number :plur}}

All morphological rules are a Clojure map containing three keys:

• :g
• :p
• :agr

The value of :g (for "generate") is how to transform a canonical form like "dog" into an inflected form like "dogs".

The value of :p: (for "parse") is the reverse: how to transform an inflected form into a canonical form.

The value of :agr (for "agreement") encodes how the inflected form differs from the canonical form. For generation, the agreement information will be available in the input syntax tree, and this agreement information will be input into the generative process to produce the inflected form. For parsing, the agreement information will be unified with the lexical form to produce the syntax tree as output.