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In linguistics, morphology (//) is the study of words, how they are formed, and their relationship to other words in the same language. It analyzes the structure of words and parts of words, such as stems, root words, prefixes, and suffixes. Morphology also looks at parts of speech, intonation and stress, and the ways context can change a word's pronunciation and meaning. Morphology differs from morphological typology, which is the classification of languages based on their use of words, and lexicology, which is the study of words and how they make up a language's vocabulary.
While words, along with clitics, are generally accepted as being the smallest units of syntax, in most languages, if not all, many words can be related to other words by rules that collectively describe the grammar for that language. For example, English speakers recognize that the words dog and dogs are closely related, differentiated only by the plurality morpheme "-s", only found bound to noun phrases. Speakers of English, a fusional language, recognize these relations from their innate knowledge of English's rules of word formation. They infer intuitively that dog is to dogs as cat is to cats; and, in similar fashion, dog is to dog catcher as dish is to dishwasher. By contrast, Classical Chinese has very little morphology, using almost exclusively unbound morphemes ("free" morphemes) and depending on word order to convey meaning. (Most words in modern Standard Chinese ["Mandarin"], however, are compounds and most roots are bound.) These are understood as grammars that represent the morphology of the language. The rules understood by a speaker reflect specific patterns or regularities in the way words are formed from smaller units in the language they are using, and how those smaller units interact in speech. In this way, morphology is the branch of linguistics that studies patterns of word formation within and across languages and attempts to formulate rules that model the knowledge of the speakers of those languages.
Phonological and orthographic modifications between a base word and its origin may be partial to literacy skills. Studies have indicated that the presence of modification in phonology and orthography makes morphologically complex words harder to understand and that the absence of modification between a base word and its origin makes morphologically complex words easier to understand. Morphologically complex words are easier to comprehend when they include a base word.
Polysynthetic languages, such as Chukchi, have words composed of many morphemes. The Chukchi word "təmeyŋəlevtpəγtərkən", for example, meaning "I have a fierce headache", is composed of eight morphemes t-ə-meyŋ-ə-levt-pəγt-ə-rkən that may be glossed. The morphology of such languages allows for each consonant and vowel to be understood as morphemes, while the grammar of the language indicates the usage and understanding of each morpheme.
The discipline that deals specifically with the sound changes occurring within morphemes is morphophonology.
The history of morphological analysis dates back to the ancient Indian linguist Pāṇini, who formulated the 3,959 rules of Sanskrit morphology in the text Aṣṭādhyāyī by using a constituency grammar. The Greco-Roman grammatical tradition also engaged in morphological analysis. Studies in Arabic morphology, conducted by Marāḥ al-arwāḥ and Aḥmad b. ‘alī Mas‘ūd, date back to at least 1200 CE.
Lexemes and word forms
The term "word" has no well-defined meaning. Instead, two related terms are used in morphology: lexeme and word-form. Generally, a lexeme is a set of inflected word-forms that is often represented with the citation form in small capitals. For instance, the lexeme eat contains the word-forms eat, eats, eaten, and ate. Eat and eats are thus considered different word-forms belonging to the same lexeme eat. Eat and Eater, on the other hand, are different lexemes, as they refer to two different concepts.
Prosodic word vs. morphological word
Here are examples from other languages of the failure of a single phonological word to coincide with a single morphological word form. In Latin, one way to express the concept of 'NOUN-PHRASE1 and NOUN-PHRASE2' (as in "apples and oranges") is to suffix '-que' to the second noun phrase: "apples oranges-and", as it were. An extreme level of this theoretical quandary posed by some phonological words is provided by the Kwak'wala language.[b] In Kwak'wala, as in a great many other languages, meaning relations between nouns, including possession and "semantic case", are formulated by affixes instead of by independent "words". The three-word English phrase, "with his club", where 'with' identifies its dependent noun phrase as an instrument and 'his' denotes a possession relation, would consist of two words or even just one word in many languages. Unlike most languages, Kwak'wala semantic affixes phonologically attach not to the lexeme they pertain to semantically, but to the preceding lexeme. Consider the following example (in Kwak'wala, sentences begin with what corresponds to an English verb):[c]
kwixʔid-i-da bəgwanəmai-χ-a q'asa-s-isi t'alwagwayu
Morpheme by morpheme translation:
- kwixʔid-i-da = clubbed-PIVOT-DETERMINER
- bəgwanəma-χ-a = man-ACCUSATIVE-DETERMINER
- q'asa-s-is = otter-INSTRUMENTAL-3SG-POSSESSIVE
- t'alwagwayu = club
- "the man clubbed the otter with his club."
- accusative case marks an entity that something is done to.
- determiners are words such as "the", "this", "that".
- the concept of "pivot" is a theoretical construct that is not relevant to this discussion.)
That is, to the speaker of Kwak'wala, the sentence does not contain the "words" 'him-the-otter' or 'with-his-club' Instead, the markers -i-da (PIVOT-'the'), referring to "man", attaches not to the noun bəgwanəma ("man") but to the verb; the markers -χ-a (ACCUSATIVE-'the'), referring to otter, attach to bəgwanəma instead of to q'asa ('otter'), etc. In other words, a speaker of Kwak'wala does not perceive the sentence to consist of these phonological words:
kwixʔid i-da-bəgwanəma χ-a-q'asa s-isi-t'alwagwayu
clubbed PIVOT-the-mani hit-the-otter with-hisi-club
A central publication on this topic is the recent volume edited by Dixon and Aikhenvald (2007), examining the mismatch between prosodic-phonological and grammatical definitions of "word" in various Amazonian, Australian Aboriginal, Caucasian, Eskimo, Indo-European, Native North American, West African, and sign languages. Apparently, a wide variety of languages make use of the hybrid linguistic unit clitic, possessing the grammatical features of independent words but the prosodic-phonological lack of freedom of bound morphemes. The intermediate status of clitics poses a considerable challenge to linguistic theory.
Inflection vs. word formation
Given the notion of a lexeme, it is possible to distinguish two kinds of morphological rules. Some morphological rules relate to different forms of the same lexeme; while other rules relate to different lexemes. Rules of the first kind are inflectional rules, while those of the second kind are rules of word formation. The generation of the English plural dogs from dog is an inflectional rule, while compound phrases and words like dog catcher or dishwasher are examples of word formation. Informally, word formation rules form "new" words (more accurately, new lexemes), while inflection rules yield variant forms of the "same" word (lexeme).
The distinction between inflection and word formation is not at all clear cut. There are many examples where linguists fail to agree whether a given rule is inflection or word formation. The next section will attempt to clarify this distinction.
Word formation is a process where one combines two complete words, whereas with inflection you can combine a suffix with some verb to change its form to subject of the sentence. For example: in the present indefinite, we use ‘go’ with subject I/we/you/they and plural nouns, whereas for third person singular pronouns (he/she/it) and singular nouns we use ‘goes’. So this ‘-es’ is an inflectional marker and is used to match with its subject. A further difference is that in word formation, the resultant word may differ from its source word's grammatical category whereas in the process of inflection the word never changes its grammatical category.
Types of word formation
There is a further distinction between two primary kinds of morphological word formation: derivation and compounding. Compounding is a process of word formation that involves combining complete word forms into a single compound form. Dog catcher, therefore, is a compound, as both dog and catcher are complete word forms in their own right but are subsequently treated as parts of one form. Derivation involves affixing bound (i.e. non-independent) forms to existing lexemes, whereby the addition of the affix derives a new lexeme. The word independent, for example, is derived from the word dependent by using the prefix in-, while dependent itself is derived from the verb depend. There is also word formation in the processes of clipping in which a portion of a word is removed to create a new one, blending in which two parts of different words are blended into one, acronyms in which each letter of the new word represents a specific word in the representation i.e. NATO for North Atlantic Treaty Organization, borrowing in which words from one language are taken and used in another, and finally coinage in which a new word is created to represent a new object or concept.
Paradigms and morphosyntax
A linguistic paradigm is the complete set of related word forms associated with a given lexeme. The familiar examples of paradigms are the conjugations of verbs and the declensions of nouns. Also, arranging the word forms of a lexeme into tables, by classifying them according to shared inflectional categories such as tense, aspect, mood, number, gender or case, organizes such. For example, the personal pronouns in English can be organized into tables, using the categories of person (first, second, third); number (singular vs. plural); gender (masculine, feminine, neuter); and case (nominative, oblique, genitive).
The inflectional categories used to group word forms into paradigms cannot be chosen arbitrarily; they must be categories that are relevant to stating the syntactic rules of the language. Person and number are categories that can be used to define paradigms in English, because English has grammatical agreement rules that require the verb in a sentence to appear in an inflectional form that matches the person and number of the subject. Therefore, the syntactic rules of English care about the difference between dog and dogs, because the choice between these two forms determines which form of the verb is used. However, no syntactic rule for the difference between dog and dog catcher, or dependent and independent. The first two are nouns and the second two are adjectives.
An important difference between inflection and word formation is that inflected word forms of lexemes are organized into paradigms that are defined by the requirements of syntactic rules, and there are no corresponding syntactic rules for word formation. The relationship between syntax and morphology is called "morphosyntax" and concerns itself with inflection and paradigms, not with word formation or compounding.
Above, morphological rules are described as analogies between word forms: dog is to dogs as cat is to cats and as dish is to dishes. In this case, the analogy applies both to the form of the words and to their meaning: in each pair, the first word means "one of X", while the second "two or more of X", and the difference is always the plural form -s (or -es) affixed to the second word, signaling the key distinction between singular and plural entities.
One of the largest sources of complexity in morphology is that this one-to-one correspondence between meaning and form scarcely applies to every case in the language. In English, there are word form pairs like ox/oxen, goose/geese, and sheep/sheep, where the difference between the singular and the plural is signaled in a way that departs from the regular pattern, or is not signaled at all. Even cases regarded as regular, such as -s, are not so simple; the -s in dogs is not pronounced the same way as the -s in cats; and, in plurals such as dishes, a vowel is added before the -s. These cases, where the same distinction is effected by alternative forms of a "word", constitute allomorphy .
Phonological rules constrain which sounds can appear next to each other in a language, and morphological rules, when applied blindly, would often violate phonological rules, by resulting in sound sequences that are prohibited in the language in question. For example, to form the plural of dish by simply appending an -s to the end of the word would result in the form *[dɪʃs], which is not permitted by the phonotactics of English. In order to "rescue" the word, a vowel sound is inserted between the root and the plural marker, and [dɪʃɪz] results. Similar rules apply to the pronunciation of the -s in dogs and cats: it depends on the quality (voiced vs. unvoiced) of the final preceding phoneme.
Lexical morphology is the branch of morphology that deals with the lexicon, which, morphologically conceived, is the collection of lexemes in a language. As such, it concerns itself primarily with word formation: derivation and compounding.
There are three principal approaches to morphology and each tries to capture the distinctions above in different ways:
- Morpheme-based morphology, which makes use of an item-and-arrangement approach.
- Lexeme-based morphology, which normally makes use of an item-and-process approach.
- Word-based morphology, which normally makes use of a word-and-paradigm approach.
While the associations indicated between the concepts in each item in that list are very strong, they are not absolute.
In morpheme-based morphology, word forms are analyzed as arrangements of morphemes. A morpheme is defined as the minimal meaningful unit of a language. In a word such as independently, the morphemes are said to be in-, de-, pend, -ent, and -ly; pend is the (bound) root and the other morphemes are, in this case, derivational affixes.[d] In words such as dogs, dog is the root and the -s is an inflectional morpheme. In its simplest and most naïve form, this way of analyzing word forms, called "item-and-arrangement", treats words as if they were made of morphemes put after each other ("concatenated") like beads on a string. More recent and sophisticated approaches, such as distributed morphology, seek to maintain the idea of the morpheme while accommodating non-concatenated, analogical, and other processes that have proven problematic for item-and-arrangement theories and similar approaches.
Morpheme-based morphology presumes three basic axioms:
- Baudoin’s "single morpheme" hypothesis: Roots and affixes have the same status as morphemes.
- Bloomfield’s "sign base" morpheme hypothesis: As morphemes, they are dualistic signs, since they have both (phonological) form and meaning.
- Bloomfield's "lexical morpheme" hypothesis: morphemes, affixes and roots alike are stored in the lexicon.
Morpheme-based morphology comes in two flavours, one Bloomfieldian and one Hockettian. For Bloomfield, the morpheme was the minimal form with meaning, but did not have meaning itself.[clarification needed] For Hockett, morphemes are "meaning elements", not "form elements". For him, there is a morpheme plural using allomorphs such as -s, -en and -ren. Within much morpheme-based morphological theory, the two views are mixed in unsystematic ways so a writer may refer to "the morpheme plural" and "the morpheme -s" in the same sentence.
Lexeme-based morphology usually takes what is called an item-and-process approach. Instead of analyzing a word form as a set of morphemes arranged in sequence, a word form is said to be the result of applying rules that alter a word-form or stem in order to produce a new one. An inflectional rule takes a stem, changes it as is required by the rule, and outputs a word form; a derivational rule takes a stem, changes it as per its own requirements, and outputs a derived stem; a compounding rule takes word forms, and similarly outputs a compound stem.
Word-based morphology is (usually) a word-and-paradigm approach. The theory takes paradigms as a central notion. Instead of stating rules to combine morphemes into word forms or to generate word forms from stems, word-based morphology states generalizations that hold between the forms of inflectional paradigms. The major point behind this approach is that many such generalizations are hard to state with either of the other approaches. Word-and-paradigm approaches are also well-suited to capturing purely morphological phenomena, such as morphomes. Examples to show the effectiveness of word-based approaches are usually drawn from fusional languages, where a given "piece" of a word, which a morpheme-based theory would call an inflectional morpheme, corresponds to a combination of grammatical categories, for example, "third-person plural". Morpheme-based theories usually have no problems with this situation since one says that a given morpheme has two categories. Item-and-process theories, on the other hand, often break down in cases like these because they all too often assume that there will be two separate rules here, one for third person, and the other for plural, but the distinction between them turns out to be artificial. The approaches treat these as whole words that are related to each other by analogical rules. Words can be categorized based on the pattern they fit into. This applies both to existing words and to new ones. Application of a pattern different from the one that has been used historically can give rise to a new word, such as older replacing elder (where older follows the normal pattern of adjectival superlatives) and cows replacing kine (where cows fits the regular pattern of plural formation).
In the 19th century, philologists devised a now classic classification of languages according to their morphology. Some languages are isolating, and have little to no morphology; others are agglutinative whose words tend to have lots of easily separable morphemes; others yet are inflectional or fusional because their inflectional morphemes are "fused" together. That leads to one bound morpheme conveying multiple pieces of information. A standard example of an isolating language is Chinese. An agglutinative language is Turkish. Latin and Greek are prototypical inflectional or fusional languages.
It is clear that this classification is not at all clearcut, and many languages (Latin and Greek among them) do not neatly fit any one of these types, and some fit in more than one way. A continuum of complex morphology of language may be adopted.
The three models of morphology stem from attempts to analyze languages that more or less match different categories in this typology. The item-and-arrangement approach fits very naturally with agglutinative languages. The item-and-process and word-and-paradigm approaches usually address fusional languages.
As there is very little fusion involved in word formation, classical typology mostly applies to inflectional morphology. Depending on the preferred way of expressing non-inflectional notions, languages may be classified as synthetic (using word formation) or analytic (using syntactic phrases).
Pingelapese is a Micronesian language spoken on the Pingelap atoll and on two of the eastern Caroline Islands, called the high island of Pohnpei. Similar to other languages, words in Pingelapese can take different forms to add to or even change its meaning. Verbal suffixes are morphemes added at the end of a word to change its form. Prefixes are those that are added at the front. For example, the Pingelapese suffix –kin means ‘with’ or 'at.’ It is added at the end of a verb.
ius = to use --> ius-kin = to use with
mwahu = to be good --> mwahu-kin = to be good at
sa- is an example of a verbal prefix. It is added to the beginning of a word and means ‘not.’
pwung = to be correct --> sa-pwung = to be incorrect
There are also directional suffixes that when added to the root word give the listener a better idea of where the subject is headed. The verb alu means to walk. A directional suffix can be used to give more detail.
-da = ‘up’ --> aluh-da = to walk up
-di = ‘down’ --> aluh-di = to walk down
-eng = ‘away from speaker and listener’ --> aluh-eng = to walk away
Directional suffixes are not limited to motion verbs. When added to non-motion verbs, their meanings are a figurative one. The following table gives some examples of directional suffixes and their possible meanings.
|Directional suffix||Motion verb||Non-motion verb|
|-da||up||Onset of a state|
|-di||down||Action has been completed|
|-la||away from||Change has caused the start of a new state|
|-doa||towards||Action continued to a certain point in time|
Morphology analysis is used in various fields. For example, using morphological features it is possible to assess data quality in Wikipedia in English, Polish, Russian and other language versions.
- Für die lere von der wortform wäle ich das wort « morphologie», nach dem vorgange der naturwißenschaften [...] (Standard High German "Für die Lehre von der Wortform wähle ich das Wort „Morphologie“, nach dem Vorgange der Naturwissenschaften [...]", "For the science of word-formation, I choose the term "morphology"...."
- Formerly known as Kwakiutl, Kwak'wala belongs to the Northern branch of the Wakashan language family. "Kwakiutl" is still used to refer to the tribe itself, along with other terms.
- Example taken from Foley (1998) using a modified transcription. This phenomenon of Kwak'wala was reported by Jacobsen as cited in van Valin & LaPolla (1997).
- The existence of words like appendix and pending in English does not mean that the English word depend is analyzed into a derivational prefix de- and a root pend. While all those were indeed once related to each other by morphological rules, that was only the case in Latin, not in English. English borrowed such words from French and Latin but not the morphological rules that allowed Latin speakers to combine de- and the verb pendere 'to hang' into the derivative dependere.
- Aronoff, Mark (1993). Morphology by Itself. Cambridge, MA: MIT Press. ISBN 9780262510721.
- Aronoff, Mark (2009). "Morphology: an interview with Mark Aronoff" (PDF). ReVEL. 7 (12). ISSN 1678-8931. Archived from the original (PDF) on 2011-07-06..
- Åkesson, Joyce (2001). Arabic morphology and phonology: based on the Marāḥ al-arwāḥ by Aḥmad b. ʻAlī b. Masʻūd. Leiden, The Netherlands: Brill. ISBN 9789004120280.
- Bauer, Laurie (2003). Introducing linguistic morphology (2nd ed.). Washington, DC: SGeorgetown University Press. ISBN 0-87840-343-4.
- Bauer, Laurie (2004). A glossary of morphology. Washington, DC: Georgetown University Press.
- Bloomfield, Leonard (1933). Language. New York: Henry Holt. OCLC 760588323.
- Bubenik, Vit (1999). An introduction to the study of morphology. LINCOM coursebooks in linguistics, 07. Muenchen: LINCOM Europa. ISBN 3-89586-570-2.
- Dixon, R. M. W.; Aikhenvald, Alexandra Y., eds. (2007). Word: A cross-linguistic typology. Cambridge: Cambridge University Press.
- Foley, William A (1998). Symmetrical Voice Systems and Precategoriality in Philippine Languages (Speech). Voice and Grammatical Functions in Austronesian. University of Sydney.
- Hockett, Charles F. (1947). "Problems of morphemic analysis". Language. 24: 414–441.
- Fabrega, Antonio; Scalise, Sergio (2012). Morphology: from Data to Theory. Edinburgh: Edinburgh University Press.
- Katamba, Francis (1993). Morphology. New York: St. Martin's Press. ISBN 0-312-10356-5.
- Korsakov, Andrey Konstantinovich (1969). "The use of tenses in English". In Korsakov, Andrey Konstantinovich (ed.). Structure of Modern English pt. 1.
- Kishorjit, N; Vidya Raj, RK; Nirmal, Y; Sivaji, B. (December 2012). Manipuri Morpheme Identification (PDF) (Speech). Proceedings of the 3rd Workshop on South and Southeast Asian Natural Language Processing (SANLP). Mumbai: COLING.
- Matthews, Peter (1991). Morphology (2nd ed.). Cambridge University Press. ISBN 0-521-42256-6.
- Mel'čuk, Igor A (1993). Cours de morphologie générale (in French). Montreal: Presses de l'Université de Montréal.
- Mel'čuk, Igor A (2006). Aspects of the theory of morphology. Berlin: Mouton.
- Scalise, Sergio (1983). Generative Morphology. Dordrecht: Foris.
- Singh, Rajendra; Starosta, Stanley, eds. (2003). Explorations in Seamless Morphology. SAGE. ISBN 0-7619-9594-3.
- Spencer, Andrew (1991). Morphological theory: an introduction to word structure in generative grammar. Blackwell textbooks in linguistics. Oxford: Blackwell. ISBN 0-631-16144-9.
- Spencer, Andrew; Zwicky, Arnold M., eds. (1998). The handbook of morphology. Blackwell handbooks in linguistics. Oxford: Blackwell. ISBN 0-631-18544-5.
- Stump, Gregory T. (2001). Inflectional morphology: a theory of paradigm structure. Cambridge studies in linguistics. Cambridge University Press. ISBN 0-521-78047-0.
- van Valin, Robert D.; LaPolla, Randy (1997). Syntax : Structure, Meaning And Function. Cambridge University Press.
- Jones, Daniel (2003) , Peter Roach; James Hartmann; Jane Setter (eds.), English Pronouncing Dictionary, Cambridge: Cambridge University Press, ISBN 3-12-539683-2
- Anderson, Stephen R. (n.d.). "Morphology". Encyclopedia of Cognitive Science. Macmillan Reference, Ltd., Yale University. Retrieved 30 July 2016.
- Aronoff, Mark; Fudeman, Kirsten (n.d.). "Morphology and Morphological Analysis" (PDF). What is Morphology?. Blackwell Publishing. Retrieved 30 July 2016.
- Brown, Dunstan (December 2012) . "Morphological Typology" (PDF). In Jae Jung Song (ed.). The Oxford Handbook of Linguistic Typology. pp. 487–503. doi:10.1093/oxfordhb/9780199281251.013.0023. Retrieved 30 July 2016.
- Sankin, A.A. (1979) . "I. Introduction" (PDF). In Ginzburg, R.S.; Khidekel, S.S.; Knyazeva, G. Y.; Sankin, A.A. (eds.). A Course in Modern English Lexicology (Revised and Enlarged, Second ed.). Moscow: VYSŠAJA ŠKOLA. p. 7. Retrieved 30 July 2016.
- Wilson-Fowler, E.B., & Apel, K. (2015). "Influence of Morphological Awareness on College Students' Literacy Skills: A path Analytic Approach". Journal of Literacy Research. 47 (3): 405–32. doi:10.1177/1086296x15619730.
- Beard, Robert (1995). Lexeme-Morpheme Base Morphology: A General Theory of Inflection and Word Formation. Albany: NY: State University of New York Press. pp. 2, 3. ISBN 0-7914-2471-5.
- Åkesson 2001.
- Schleicher, August (1859). "Zur Morphologie der Sprache". Mémoires de l'Académie Impériale des Sciences de St.-Pétersbourg. VII°. I, N.7. St. Petersburg. p. 35.
- Haspelmath & Sims 2002, p. 15.
- Haspelmath & Sims 2002, p. 16.
- Anderson, Stephen R. A-Morphous Morphology. Cambridge: Cambridge University Press. p. 74, 75.
- Plag, Ingo (2003). "Word Formation in English" (PDF). Library of Congress. Cambridge. Retrieved 2016-11-30.
- Haspelmath, Martin; Sims, Andrea D. (2002). Understanding Morphology. London: Arnold. ISBN 0-340-76026-5.
- Beard 1995.
- Bloomfield 1993. Harv error: no target: CITEREFBloomfield1993 (help)
- Hockett 1947.
- Bybee, Joan L. (1985). Morphology: A Study of the Relation Between Meaning and Form. Amsterdam: John Benjamins. pp. 11, 13.
- Hattori, Ryoko (2012). Preverbal Particles in Pingelapese. pp. 31–33.
- Biber, D., Conrad, S., & Reppen, R. (1998). Corpus linguistics: Investigating language structure and use. Cambridge University Press.
- Gries, S. T., Wulff, S., & Davies, M. (2010). Corpus-linguistic applications:" Current studies, new directions". BRILL.
- Xu, Y., Luo, T. (2011). Measuring article quality in Wikipedia: Lexical clue model. In: 2011 3rd Symposium on Web Society (SWS), pp. 141–146. IEEE.
- Lewoniewski, Włodzimierz; Węcel, Krzysztof; Abramowicz, Witold (2018). "Determining Quality of Articles in Polish Wikipedia Based on Linguistic Features". Communications in Computer and Information Science. 920: 546–558. doi:10.1007/978-3-319-99972-2_45. ISBN 978-3-319-99971-5. Retrieved 2019-01-13.
- Lewoniewski, Włodzimierz; Khairova, Nina; Węcel, Krzysztof; Stratiienko, Nataliia; Abramowicz, Witold (2017-09-23). "Using Morphological and Semantic Features for the Quality Assessment of Russian Wikipedia". Communications in Computer and Information Science. 756: 550–560. doi:10.1007/978-3-319-67642-5_46. ISBN 978-3-319-67641-8. Retrieved 2019-01-13.