{{short description|Part of a word responsible for its lexical meaning}}
In linguistics, a '''word stem''' is a word part responsible for a word's lexical meaning. The term is used with slightly different meanings depending on the morphology of the language in question. For instance, in Athabaskan linguistics, a verb stem is a root that cannot appear on its own and that carries the tone of the word.
Typically, a stem remains unmodified during inflection with few exceptions due to apophony (for example in Polish, {{lang|pl|miast-o}} ("city") and {{lang|pl|w mieści-e}} ("in the city"); in English, ''sing'', ''sang'', and ''sung'', where it can be modified according to morphological rules or peculiarities, such as sandhi).
Word stem comparisons across languages have helped reveal cognates that have allowed comparative linguists to determine language families and their history.<ref name="AHD_IndoEuropRoots">{{Citation |author=Houghton Mifflin Harcourt |title=The American Heritage Dictionary of the English Language: Indo-European Roots Appendix |publisher=Houghton Mifflin Harcourt |url=https://ahdictionary.com/word/indoeurop.html |postscript=.}}</ref>
==Root vs stem== The word ''friendship'' is made by attaching the morpheme ''-ship'' to the root word ''friend'' (which some linguists<ref>{{cite book|title=The 'language instinct' debate|author=Geoffrey Sampson|author-link=Geoffrey Sampson|author2=Paul Martin Postal|author2-link=Paul Martin Postal|year=2005|publisher=Continuum International Publishing Group|isbn=978-0-8264-7385-1|page=124|url=https://books.google.com/books?id=N0zJNPuXTZMC&pg=PA124 |access-date=2009-07-21}}</ref> also call a stem). While the inflectional plural morpheme ''-s'' can be attached to ''friendship'' to form ''friendships'', it can not be attached to the root ''friend'' within ''friendship'' to form ''friendsship''. A stem is a base from which all its inflected variants are formed.<ref>{{cite book|title=Analyzing grammar|author=Paul Kroeger|year=2005|publisher=Cambridge University Press|isbn=978-0-521-81622-9|page=248|url=https://books.google.com/books?id=rSglHbBaNyAC&pg=PA248 |access-date=2009-07-21}}</ref> For example, the ''stabil-'' (a variant of ''stable'' unable to stand alone) is the root of the ''destabilized'', while the stem consists of ''de·stabil·ize'', including ''de-'' and ''-ize''. The ''-(e)d'', on the other hand, is not part of the stem.
A stem can be a lone root, such as the verb ''run;'' a compound of roots, such as the compound nouns ''meatball'' and ''bottleneck;'' or a derivation with affixes, such as the verbs ''blacken'' and ''standardize''.
The stem of the verb ''to wait'' is ''wait'': The stem is the word part that is common to all of its inflected variants. #''wait'' (infinitive, imperative, present subjunctive, and present indicative except in the 3rd-person singular) #''wait''s (third person singular of the simple present indicative) #''wait''ed (simple past) #''wait''ed (past participle) #''wait''ing (present participle)
== Citation forms and bound morphemes == {{main|Lemma (morphology)}}
In languages with very little inflection, such as English and Chinese, the stem is usually not distinct from the "normal" form of the word (the lemma, citation, or dictionary form). However, in other languages, word stems may rarely or never occur on their own. For example, the English verb stem ''run'' is indistinguishable from its present tense form (except in the third person singular). However, the equivalent Spanish verb stem ''corr-'' never appears as such because it is cited with the infinitive inflection (''correr'') and always appears in actual speech as a non-finite (infinitive or participle) or conjugated form. Such morphemes that cannot occur on their own in this way are usually referred to as ''bound morphemes''.
In computational linguistics, the term "stem" is used for the part of the word that never changes, even morphologically, when inflected, and a lemma is the base form of the word.{{citation needed|date=May 2018}} For example, given the word "produced", its lemma (linguistics) is "produce", but the stem is "produc-" because of the inflected form "producing".
== Paradigms and suppletion == A list of all the inflected forms of a word stem is called its inflectional paradigm. The paradigm of the adjective ''tall'' is given below, and the stem of this adjective is ''tall''. *tall (positive); taller (comparative); tallest (superlative) Some paradigms do not make use of the same stem throughout; this phenomenon is called suppletion. An example of a suppletive paradigm is the paradigm for the adjective ''good'': its stem changes from ''good'' to the bound morpheme ''bet-''. *good (positive); better (comparative); best (superlative)
== Oblique stem {{anchor|Oblique stem}}== Both in Latin and Greek, the declension (inflection) of some nouns uses a different stem in the oblique cases than in the nominative and vocative singular cases. Such words belong to, respectively, the so-called third declension of the Latin grammar and the so-called third declension of the Ancient Greek grammar. For example, the genitive singular is formed by adding ''-is'' (Latin) or -ος (Greek) to the oblique stem, and the genitive singular is conventionally listed in Greek and Latin dictionaries to illustrate the oblique.
===Examples===
{{col-begin|width=100%}} {{col-2}} {| class="wikitable" |- ! Latin word ! meaning ! oblique stem |- | ''adeps'' | fat | ''adip-'' |- | ''altitudo'' | height | ''altitudin-'' |- | ''index'' | pointer | ''indic-'' |- | ''rex'' | king, ruler | ''reg-'' |- |''supellex'' |equipment, furniture | ''supellectil-'' |} {{col-2}} {| class="wikitable" |- ! Greek word ! meaning ! oblique stem |- | ἄναξ (ánax) | lord | ἄνακτ- (ánakt-) |- | ἀνήρ (anḗr) | man | ἀνδρ- (andr-) |- | κάλπις (kálpis) | jug | κάλπιδ- (kálpid-) |- | μάθημα (máthēma) | learning | μαθήματ- (mathḗmat-) |} {{col-end}}
English words derived from Latin or Greek often involve the oblique stem: ''<u>adip</u>ose'', ''<u>altitudin</u>al'', ''<u>andr</u>oid'', and ''<u>mathemat</u>ics''.
Historically, the difference in stems arose due to sound changes in the nominative. In the Latin third declension, for example, the nominative singular suffix ''-s'' is combined with a stem-final consonant. If that consonant was ''c'', the result was ''x'' (a mere orthographic change), while if it was ''g'', the ''-s'' caused it to devoice, again resulting in ''x''. If the stem-final consonant was another alveolar consonant (''t, d, r''), it elided before the ''-s''. In a later era, ''n'' before the nominative ending was also lost, producing pairs like ''atlas, atlant-'' (for English Atlas, Atlantic).
== See also == * Lemma (morphology) * Lexeme * Morphological typology * Morphology (linguistics) * Principal parts * Root (linguistics) * Stemming algorithms (computer science) * Thematic vowel
== References ==
{{Reflist}} * [https://glossary.sil.org/term/stem What is a stem?] – SIL International, Glossary of Linguistic Terms. * Bauer, Laurie (2003) ''Introducing Linguistic Morphology''. Georgetown University Press; 2nd edition. * Williams, Edwin and Anna-Maria DiScullio (1987) ''On the definition of a word.'' Cambridge MA, MIT Press.
== External links == {{wiktionary|Appendix:List of Proto-Semitic stems}} * [http://www.prefixsuffix.com/ Searchable reference for word stems including affixes (prefixes and suffixes)]
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Category:Morphemes Category:Linguistics terminology