In the fields of computational linguistics and applied linguistics, a morphological dictionary is a linguistic resource that contains correspondences between surface form and lexical forms of words. Surface forms of words are those found in natural language text. The corresponding lexical form of a surface form is the lemma followed by grammatical information (for example the part of speech, gender and number). In English give, gives, giving, gave and given are surface forms of the verb give. The lexical form would be "give", verb. There are two kinds of morphological dictionaries: morpheme-aligned dictionaries and full-form (non-aligned) dictionaries.
Notable examples and formalisms
Universal Morphologies
Inspired by the success of the Universal Dependencies for cross-linguistic annotation of syntactic dependencies, similar efforts have emerged for morphology, e.g., UniMorph and UDer. These feature simple tabular (tab-separated) formats with one form in a row, and its derivation (UDer), resp., inflection information (UniMorph):aalen aalend V.PTCP;PRS
aalen aalen V;IND;PRS;1;PL
aalen aalen V;IND;PRS;3;PL
aalen aalen V;NFIN
(UniMorph, German. Columns are LEMMA, FORM, FEATURES)In UDer, additional information (part of speech) is encoded within the columns:abändern_V Abänderung_Nf dVN07>
Abarbeiten_Nn abarbeiten_V dNV09>
abartig_A Abartigkeit_Nf dAN03>
Abart_Nf abartig_A dNA05>
abbaggern_V Abbaggern_Nn dVN09>
(UDer, German DErivBase 0.5. Columns are BASE, DERIVED, RULE)At the time of writing (2021), all of these are non-aligned morphological dictionaries (see below). Their simplistic format is particularly well-suited for the application of machine learning techniques, and UniMorph in particular, has been subject of numerous shared tasks.
Finite State Transducers
Finite State Transducers (FSTs) are a popular technique for the computational handling of morphology, esp., inflectional morphology. In rule-based morphological parsers, both lexicon and rules are normally formalized as finite state automata and subsequently combined. They thus require morphological dictionaries with specific processing instructions (which often have a linguistic interpretation, but, technically, are just treated like arbitrary string symbols). Popular FST packages such as SFST (as available from the fst package in Debian and Ubuntu) allow to define application-specific file formats for morphological lexica, that bundle different pieces of morphological information with every individual morpheme. These are thus aligned morphological dictionaries, but very rich (and also, idiosyncratic) in structure.
Sample data from SMOR (German SFST grammar):<Base_Stems>Aachen<NN><base><nativ><Name-Neut_s>
<Base_Stems>Aal<NN><base><nativ><NMasc_es_e>
<Base_Stems>Aarau<NN><base><nativ><Name-Neut_s>
<Suff_Stems><suffderiv><gebunden><kompos><NN>nom<>:e<>:n<NN><SUFF><kompos><frei>
<Suff_Stems><suffderiv><gebunden><kompos><NN>nom<NN><SUFF><base><frei><NMasc_en_en>
<Suff_Stems><suffderiv><gebunden><kompos><NN>nom<NN><SUFF><deriv><frei>
Interlinear Glossed Text editors
Interlinear Glossed Text (IGT) is a popular formalism in language documentation, linguistic typology and other branches of linguistics and the philologies. Although IGT can be created without any specialized software (but just with a conventional editor), such specialized software has been developed, with notable examples such as Toolbox, the FieldWorks Language Explorer (FLEx) or open source alternatives such as Xigt. Toolbox and FLEx support semi-automated annotation by means of an internal morphological dictionary. Whenever a morphological segment is encountered for which an annotation in the dictionary can be found, this annotations is applied. Whenever a morphological segment is newly annotated, the annotation is stored in the dictionary. FLEx and Toolbox provide different editor functionalities for annotating text and editing dictionaries, so that additional information beyond that found in annotations can be added, but at its core, their formats provide aligned morphological dictionaries.