Open class (linguistics)
In linguistics, a word class may be either an open class or a closed class. Open classes accept the addition of new morphemes (words), through such processes as compounding, derivation, inflection, coining, and borrowing; closed classes generally do not.
Content words, or lexical words, (including nouns, verbs, adjectives, and most adverbs) are words that carry the content or the meaning of a sentence and are open-class words. Newly invented nouns, verbs, and adjectives are considered open-class words, and are always able to be used grammatically in a sentence. They contrast with function words, such as articles, prepositions, conjunctions, auxiliary verbs, and pronouns, which can be found in almost any utterance, no matter what it is about. Words in open classes (content/lexical words) carry the primary communicative force of an utterance. These words are usually variable in form (inflected), especially in inflecting languages. Their distribution is not definable by the grammar.
Typical open classes are the class of nouns, the class of verbs, the class of adjectives, and the class of adverbs. However, this varies between languages; for example, in Japanese, pronouns form an open class (the distinction between nouns and pronouns is not always clear in Japanese), while verbs form a closed class. With a few exceptions, such as サボる (saboru, "to ditch class") and ぐぐる (guguru, "to google"), new "verbs" in Japanese are formed by appending する (suru, "to do") to a noun.
Open-class words are not considered part of the core language and as such they can be changed, replaced or dropped from the common lexicon, which can encompass many thousands of them. For living languages, this change is noticeable within an individual lifespan, and usually faster. Closed-class words, on the other hand, are always relatively few and resistant to change. They are unproductively and are generally invariable in form (except demonstratives, modals and some pronouns).
English open word classes
In English, open classes include the following parts of speech:
- Hoff, Erika (2014). Language Development. Belmont, CA: Cengage Learning. p. 171. ISBN 978-1-133-93909-2.
- http://strazny.com/encyclopedia/sample-function-words.html Open class words
- http://www.ucl.ac.uk/internet-grammar/wordclas/open.htm Open and Closed Word Classes