Affix in the context of Null morpheme

A word is a basic element of language that carries meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of what a word is, there is no consensus among linguists on its definition and numerous attempts to find specific criteria of the concept remain controversial. Different standards have been proposed, depending on the theoretical background and descriptive context; these do not converge on a single definition. Some specific definitions of the term "word" are employed to convey its different meanings at different levels of description, for example based on phonological, grammatical or orthographic basis. Others suggest that the concept is simply a convention used in everyday situations.

The concept of "word" is distinguished from that of a morpheme, which is the smallest unit of language that has a meaning, even if it cannot stand on its own. Words are made out of at least one morpheme. Morphemes can also be joined to create other words in a process of morphological derivation. In English and many other languages, the morphemes that make up a word generally include at least one root (such as "rock", "god", "type", "writ", "can", "not") and possibly some affixes ("-s", "un-", "-ly", "-ness"). Words with more than one root ("[type][writ]er", "[cow][boy]s", "[tele][graph]ically") are called compound words. Contractions ("can't", "would've") are words formed from multiple words made into one. In turn, words are combined to form other elements of language, such as phrases ("a red rock", "put up with"), clauses ("I threw a rock"), and sentences ("I threw a rock, but missed").

A morpheme is any of the smallest meaningful constituents within a linguistic expression and particularly within a word. Many words are themselves standalone morphemes, while other words contain multiple morphemes; in linguistic terminology, this is the distinction, respectively, between free and bound morphemes. The field of linguistic study dedicated to morphemes is called morphology.

In English, inside a word with multiple morphemes, the main morpheme that gives the word its basic meaning is called a root (such as cat inside the word cats), which can be bound or free. Meanwhile, additional bound morphemes, called affixes, may be added before or after the root, like the -s in cats, which indicates plurality but is always bound to a root noun and is not regarded as a word on its own. However, in some languages, including English and Latin, even many roots cannot stand alone; i.e., they are bound morphemes. For instance, the Latin root reg- ('king') must always be suffixed with a case marker: regis, regi, rex (reg+s), etc. The same is true of the English root nat(e) — ultimately inherited from a Latin root meaning "birth, born" — which appears in words like native, nation, nature, innate, and neonate.

A lexicon (pl. lexicons, rarely lexica) is the vocabulary of a language or branch of knowledge (such as nautical or medical). In linguistics, a lexicon is a language's inventory of lexemes. The word lexicon derives from Greek word λεξικόν (lexikon), neuter of λεξικός (lexikos) meaning 'of or for words'.

Linguistic theories generally regard human languages as consisting of two parts: a lexicon, essentially a catalogue of a language's words (its wordstock); and a grammar, a system of rules which allow for the combination of those words into meaningful sentences. The lexicon is also thought to include bound morphemes, which cannot stand alone as words (such as most affixes). In some analyses, compound words and certain classes of idiomatic expressions, collocations and other phrasemes are also considered to be part of the lexicon. Dictionaries are lists of the lexicon, in alphabetical order, of a given language; usually, however, bound morphemes are not included.

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.

The basic fields of linguistics broadly focus on language structure at different "scales". Morphology is considered to operate at a scale larger than phonology, which investigates the categories of speech sounds that are distinguished within a spoken language, and thus may constitute the difference between a morpheme and another. Conversely, syntax is concerned with the next-largest scale, and studies how words in turn form phrases and sentences. Morphological typology is a distinct field that categorises languages based on the morphological features they exhibit.

In linguistic morphology, inflection (less commonly, inflexion) is a process of word formation in which a word is modified to express different grammatical categories such as tense, case, voice, aspect, person, number, gender, mood, animacy, and definiteness. The inflection of verbs is called conjugation, while the inflection of nouns, adjectives, adverbs, etc. can be called declension.

An inflection expresses grammatical categories with affixation (such as prefix, suffix, infix, circumfix, and transfix), apophony (as Indo-European ablaut), or other modifications. For example, the Latin verb ducam, meaning "I will lead", includes the suffix -am, expressing person (first), number (singular), and tense-mood (future indicative or present subjunctive). The use of this suffix is an inflection. In contrast, in the English clause "I will lead", the word lead is not inflected for any of person, number, or tense; it is simply the bare form of a verb. The inflected form of a word often contains both one or more free morphemes (a unit of meaning which can stand by itself as a word), and one or more bound morphemes (a unit of meaning which cannot stand alone as a word). For example, the English word cars is a noun that is inflected for number, specifically to express the plural; the content morpheme car is unbound because it could stand alone as a word, while the suffix -s is bound because it cannot stand alone as a word. These two morphemes together form the inflected word cars.

Lexical semantics (also known as lexicosemantics), 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.

The units of analysis in lexical semantics are lexical units which include not only words but also sub-words or sub-units such as affixes and even compound words and phrases. Lexical units include the catalogue of words in a language, the lexicon. Lexical semantics looks at how the meaning of the lexical units correlates with the structure of the language or syntax. This is referred to as syntax-semantics interface.

Determiner, also called determinative (abbreviated DET), is a term used in some models of grammatical description to describe a word or affix belonging to a class of noun modifiers. A determiner combines with a noun to express its reference. Examples in English include articles (the and a/an), demonstratives (this, that), possessive determiners (my, their), and quantifiers (many, both). Not all languages have determiners, and not all systems of grammatical description recognize them as a distinct category.

A prefix is an affix which is placed before the stem of a word. Particularly in the study of languages, a prefix is also called a preformative, because it alters the form of the word to which it is affixed.

Prefixes, like other affixes, can be either inflectional, creating a new form of a word with the same basic meaning and same lexical category, or derivational, creating a new word with a new semantic meaning and sometimes also a different lexical category. Prefixes, like all affixes, are usually bound morphemes.

In linguistics, a suffix is an affix which is placed after the stem of a word. Common examples are case endings, which indicate the grammatical case of nouns and adjectives, and verb endings, which form the conjugation of verbs.

Suffixes can carry grammatical information (inflectional endings) or lexical information (derivational/lexical suffixes). Inflection changes the grammatical properties of a word within its syntactic category. Derivational suffixes fall into two categories: class-changing derivation and class-maintaining derivation.

A word family is the base form of a word plus its inflected forms and derived forms made with suffixes and prefixes plus its cognates, i.e. all words that have a common etymological origin, some of which even native speakers don't recognize as being related (e.g. "wrought (iron)" and "work(ed)"). In the English language, inflectional affixes include third person -s, verbal -ed and -ing, plural -s, possessive -s, comparative -er and superlative -est. Derivational affixes include -able, -er, -ish, -less, -ly, -ness, -th, -y, non-, un-, -al, -ation, -ess, -ful, -ism, -ist, -ity, -ize/-ise, -ment, in-. The idea is that a base word and its inflected forms support the same core meaning, and can be considered learned words if a learner knows both the base word and the affix.Bauer and Nation proposed seven levels of affixes based on their frequency in English. It has been shown that word families can assist with deriving related words via affixes, along with decreasing the time needed to derive and recognize such words.

Neoclassical compounds are compound words composed from combining forms (which act as affixes or stems) derived from classical languages (classical Latin or ancient Greek) roots. Neo-Latin comprises many such words and is a substantial component of the technical and scientific lexicon of English and other languages, via international scientific vocabulary (ISV). For example, Greek bio- combines with -graphy to form biography ("life" + "writing/recording").

In linguistics, an honorific (abbreviated HON) is a grammatical or morphosyntactic form that encodes the relative social status of the participants of the conversation. Distinct from honorific titles, linguistic honorifics convey formality FORM, social distance, politeness POL, humility HBL, deference, or respect through the choice of an alternate form such as an affix, clitic, grammatical case, change in person or number, or an entirely different lexical item. A key feature of an honorific system is that one can convey the same message in both honorific and familiar forms—i.e., it is possible to say something like (as in an oft-cited example from Brown and Levinson) "The soup is hot" in a way that confers honor or deference on one of the participants of the conversation.

Honorific speech is a type of social deixis, as an understanding of the context—in this case, the social status of the speaker relative to the other participants or bystanders—is crucial to its use.

Fusional languages or inflected languages are a type of synthetic language, distinguished from agglutinative languages by their tendency to use single inflectional morphemes to denote multiple grammatical, syntactic, or semantic features.

For example, the Spanish verb comer ("to eat") has the active first-person singular indicative preterite tense form comí ("I ate") where just one suffix, -í, denotes the intersection of the active voice, the first person, the singular number, the indicative mood, and preterite (which is the combination of the past tense and perfective aspect), instead of having a separate affix for each feature.

In linguistics, evidentiality is, broadly, the indication of the nature of evidence for a given statement; that is, whether evidence exists for the statement and if so, what kind. An evidential (also verificational or validational) is the particular grammatical element (affix, clitic, or particle) that indicates evidentiality. Languages with only a single evidential have had terms such as mediative, médiatif, médiaphorique, and indirective used instead of evidential.

Evidentiality may be direct or indirect: direct evidentials are used to describe information directly perceived by the speaker through vision as well as other sensory experiences while indirect evidentials consist of the other grammatical markers for evidence such as quotatives and inferentials.