| 81 | Linguistics and languages |
| 81;1 |
| 81;39 | Ethnolinguistics |
| 81-112 | Diachronic linguistics (historical linguistics) |
| 81-115 |
| 81-13 | Methodology of linguistics. Methods and means |
| 81-23 |
| 81-24 |
| 81-25 | Colloquial language |
| 81’0 | Special auxiliary numbers for origins and periods of languages |
| 81’01 | Old period. Archaic period |
| 81’02 | Classical period |
| 81’04 | Middle period |
| 81’06 | Modern period |
| 81’1 | General linguistics |
| 81`1(072) | Linguistics.Documentary materials for teaching. Teaching aids |
| 81`1(075) | Linguistics.Educational texts. Schoolbooks. Texts for students |
| 81`1(075) | Linguistics.Textbooks |
| 81`1(075.2) | Linguistics.Schoolbooks |
| 81’1(075.8) | Linguistics.Texts for students |
| 81’1(09) | Linguistics.Historiography |
| 81’1:061.4(100) →81’1(063) | Linguistics.Congresses |
| 81’22 | General theory of signs in relation to linguistics. Semiology. Semiotics |
| 81’221.2 | Sign language |
| 81’23 | Psycholinguistics. Psychology of language |
| 81’24 | Practical knowledge of languages |
| 81’242 | Native language |
| 81’243 | Foreign language. |
| 81’246 | Monolingualism. Bilingualism |
| 81’246.1 | Monolingualism |
| 81’246.2 | Bilingualism |
| 81’246.3 | Multilingualism |
| 81’25 | Theory of translation |
| 81’253 | Simultaneous interpreting |
| 81’255 |
| 81’255.2 | Literary translation |
| 81’255.4 | Stylistics of translation |
| 81`27 | Sociolinguistics. Usage of language |
| 81’271.2 | Linguistic culture |
| 81’272 | Language policy |
| 81’276 | Sociolect.Slang.Jargon |
| 81’28 | Dialectology. Geographical linguistics. Areal linguistics |
| 81’33 | Applied linguistics |
| 81’34 | Phonetics. Phonology |
| 81’342 | Phonetics |
| 81’35 | Graphemics. Orthography. Spelling |
| 81’351 | Alphabets |
| 81’36 | Grammar |
| 81’362 | Grammar, Comparative |
| 81’366 | Morphology. |
| 81’367 | Syntax |
| 81’367.3 | Sentnces |
| 81’367.6 | Parts of speech |
| 81’37 | Semantics |
| 81’373 | Lexicology |
| 81’373.2 | Onomastics |
| 81’373.21 | Names, Geographical. |
| 81’373.231 | Names, Personal |
| 81’373.4 | Word (Linguistics) |
| 81’373.42 | Synonyms.Antonyms.Homonyms.Homograph |
| 81’373.6 | Etymology. |
| 81’374 | Lexicography .Dictionaries. |
| 81’374.2 | Typs of dictionaries |
| 81’374.221 | Dictionaries of synonyms (thesauri) |
| 81’374.3 | Explanatory dictionary |
| 81’374.4 | Etymological dictionary |
| 81’374.5 | Phonetic dictionary |
| 81’374.8 |
| 81’374.81 |
| 81’374.82 |
| 81’374.822 | Bilingual dictionaries |
| 81’374.823 | Multilingual dictionary |
| 81’38 | General stylistics |
| 811 | Languages |
| 811.1/.8 | Individual natural languages |
| 811.1/.2 | Indo-European languages |
| 811.11 | Germanic languages |
| 811.111 | English language |
| 811.111(072) |
| 811.111(075) |
| 811.111(075)->(076.5) |
| 811.111(075.2) |
| 811.111(075.8) |
| 811.111(082) |
| 811.111(09) |
| 811.111=025 |
| 811.111’01 |
| 811.111’04 |
| 811.111’28 |
| 811.111’342 |
| 811.111’35 |
| 811.111’36 |
| 811.111’362 |
| 811.111’366 |
| 811.111’367 |
| 811.111’367.3 |
| 811.111’367.6 |
| 811.111’37 |
| 811.111’373 |
| 811.111’373.2 |
| 811.111’373.21 |
| 811.111’373.231 |
| 811.111’373.42 |
| 811.111’373.6 |
| 811.111’374 |
| 811.111’374.8 |
| 811.111’374.8=161.1 |
| 811.111’374= |
| 811.112.2 |
| 811.112.28 |
| 811.112.5 |
| 811.112.6 |
| 811.113.3 |
| 811.113.4 |
| 811.113.5 |
| 811.113.6 |
| 811.124 |
| 811.124’01 |
| 811.124’02 |
| 811.124’04 |
| 811.124’06 |
| 811.13 |
| 811.131.1 |
| 811.133.1 |
| 811.134.2 |
| 811.134.3 |
| 811.135.1 |
| 811.135.2 |
| 811.14 |
| 811.14’02 | Classical Greek |
| 811.14’03 | Koine (New Testament Greek) |
| 811.14’04 | Byzantine Greek |
| 811.14’06 | Modern Greek |
| 811.152.1 |
| 811.152.2 |
| 811.16 |
| 811.161 | East Slavic languages |
| 811.161.1 |
| 811.161.2 |
| 811.161.3 |
| 811.162 | West Slavic languages |
| 811.162.1 |
| 811.162.2 |
| 811.162.3 |
| 811.162.4 |
| 811.163 | South Slavic languages |
| 811.163.1 |
| 811.163.2 |
| 811.163.3 |
| 811.163.4 | Serbian and Croatian languages |
| 811.163.41 |
| 811.163.42 |
| 811.163.6 |
| 811.17 | Baltic languages |
| 811.172 |
| 811.174 |
| 811.18 |
| 811.19 |
| 811.21/22 |
| 811.21 | Indic languages |
| 811.211 |
| 811.211’01 |
| 811.212 |
| 811.213 |
| 811.214 |
| 811.214.21 |
| 811.214.22 |
| 811.214.27 |
| 811.214.32 |
| 811.214.58 |
| 811.22 |
| 811.221.18 |
| 811.221.31 |
| 811.222.1 |
| 811.222.1’01 |
| 811.222.1’02 |
| 811.222.1’04 | Middle Persian language |
| 811.222.1’06 | Modern Persian language |
| 811.222.5 |
| 811.222.8 |
| 811.293 |
| 811.341.1 |
| 811.341.4 |
| 811.341.6 |
| 811.35 |
| 811.351 | Northeast Caucasian languages |
| 811.351.12 |
| 811.351.21 |
| 811.351.22 |
| 811.351.32 |
| 811.351.41 |
| 811.351.42 |
| 811.351.43 |
| 811.352 | Northwest Caucasian languages |
| 811.352.1 |
| 811.352.2 |
| 811.352.3 |
| 811.353 | Southern (Kartvelian) group |
| 811.353.1 |
| 811.353.2 |
| 811.353.31 |
| 811.41 |
| 811.411 |
| 811.411.1 |
| 811.411.11 |
| 811.411.111 |
| 811.411.112 | Suret language |
| 811.411.152 |
| 811.411.16 |
| 811.411.17 |
| 811.411.172.3 |
| 811.411.172.3’06 |
| 811.411.21 |
| 811.411.41 |
| 811.412 |
| 811.412’09 |
| 811.51 | Ural-Altaic languages |
| 811.511.111 |
| 811.511.113 |
| 811.511.131 |
| 811.511.132 |
| 811.511.14 |
| 811.511.141 |
| 811.511.14 |
| 811.512 |
| 811.512.1 |
| 811.512.111 |
| 811.512.121 |
| 811.512.122 |
| 811.512.123 |
| 811.512.133 |
| 811.512.141 |
| 811.512.142 |
| 811.512.145 |
| 811.512.154 |
| 811.512.157 |
| 811.512.161 |
| 811.512.162 |
| 811.512.164 |
| 811.512.31 |
| 811.512.37 |
| 811.521 |
| 811.531 |
| 811.581 |
| 811.584.6 |
| 811.6 | Austro-Asiatic languages. Austronesian languages |
| 811.612.4 |
| 811.612.91 |
| 811.9 | Artificial languages |
| 811.921 |
| 811.922 |