Word formation

A lexicon is the vocabulary of a language or branch of knowledge. In linguistics, a lexicon is a language's inventory of lexemes. The word lexicon derives from Greek word λεξικόν, neuter of λεξικός meaning 'of or for words'.

A lexeme is a unit of lexical meaning that underlies a set of words that are related through inflection. It is a basic abstract unit of meaning, a unit of morphological analysis in linguistics that roughly corresponds to a set of forms taken by a single root word. For example, in English, run, runs, ran and running are forms of the same lexeme, which can be represented as RUN.

A morpheme is the smallest meaningful constituent of a linguistic expression. The field of linguistic study dedicated to morphemes is called morphology.

In linguistics, morphology is the study of words, including the principles by which they are formed, and how they relate to one another within a language. Most approaches to morphology investigate the structure of words in terms of morphemes, which are the smallest units in a language with some independent meaning. Morphemes include roots that can exist as words by themselves, but also categories such as affixes that can only appear as part of a larger word. For example, in English the root catch and the suffix -ing are both morphemes; catch may appear as its own word, or it may be combined with -ing to form the new word catching. Morphology also analyzes how words behave as parts of speech, and how they may be inflected to express grammatical categories including number, tense, and aspect. Concepts such as productivity are concerned with how speakers create words in specific contexts, which evolves over the history of a language.

Morphological derivation, in linguistics, is the process of forming a new word from an existing word, often by adding a prefix or suffix, such as un- or -ness. For example, unhappy and happiness derive from the root word happy.

In linguistics, function words are words that have little lexical meaning or have ambiguous meaning and express grammatical relationships among other words within a sentence, or specify the attitude or mood of the speaker. They signal the structural relationships that words have to one another and are the glue that holds sentences together. Thus they form important elements in the structures of sentences.

Lexical semantics, as a subfield of linguistic semantics, is the study of word meanings. It includes the study of how words structure their meaning, how they act in grammar and compositionality, and the relationships between the distinct senses and uses of a word.

A root is the core of a word that is irreducible into more meaningful elements. In morphology, a root is a morphologically simple unit which can be left bare or to which a prefix or a suffix can attach. The root word is the primary lexical unit of a word, and of a word family, which carries aspects of semantic content and cannot be reduced into smaller constituents. Content words in nearly all languages contain, and may consist only of, root morphemes. However, sometimes the term "root" is also used to describe the word without its inflectional endings, but with its lexical endings in place. For example, chatters has the inflectional root or lemma chatter, but the lexical root chat. Inflectional roots are often called stems. A root, or a root morpheme, in the stricter sense, may be thought of as a monomorphemic stem.

Lemmatization in linguistics is the process of grouping together the inflected forms of a word so they can be analysed as a single item, identified by the word's lemma, or dictionary form.

In linguistics, a word stem is a part of a word responsible for its lexical meaning. Typically, a stem remains unmodified during inflection with few exceptions due to apophony

Wiyot or Soulatluk (lit. 'your jaw') is an Algic language spoken by the Wiyot people of Humboldt Bay, California. The language's last native speaker, Della Prince, died in 1962.

In linguistics, especially within generative grammar, phi features are the morphological expression of a semantic process in which a word or morpheme varies with the form of another word or phrase in the same sentence. This variation can include person, number, gender, and case, as encoded in pronominal agreement with nouns and pronouns. Several other features are included in the set of phi-features, such as the categorical features ±N (nominal) and ±V (verbal), which can be used to describe lexical categories and case features.

In linguistics, the term nominal refers to a category used to group together nouns and adjectives based on shared properties. The motivation for nominal grouping is that in many languages nouns and adjectives share a number of morphological and syntactic properties. The systems used in such languages to show agreement can be classified broadly as gender systems, noun class systems or case marking, classifier systems, and mixed systems. Typically an affix related to the noun appears attached to the other parts of speech within a sentence to create agreement. Such morphological agreement usually occurs in parts within the noun phrase, such as determiners and adjectives. Languages with overt nominal agreement vary in how and to what extent agreement is required.

In linguistics and literature, periphrasis is the use of a larger number of words, with an implicit comparison to the possibility of using fewer. The comparison may be within a language or between languages. For example, "more happy" is periphrastic in comparison to "happier", and English "I will eat" is periphrastic in comparison to Spanish comeré.

In linguistic typology, polysynthetic languages, formerly holophrastic languages, are highly synthetic languages, i.e., languages in which words are composed of many morphemes. They are very highly inflected languages. Polysynthetic languages typically have long "sentence-words" such as the Yupik word tuntussuqatarniksaitengqiggtuq.

Francis X. Katamba is a Ugandan-born British linguist. He is currently an emeritus professor at the Department of Linguistics and English Language of Lancaster University, United Kingdom. His research focuses on Luganda phonology and morphology, English phonology and morphology, morphological theory, phonological theory, and African linguistics.