Grammatical aspect in the context of English verbs

In linguistics, grammatical number is a feature of nouns, pronouns, adjectives and verb agreement that expresses count distinctions (such as "one", "two" or "three or more"). English and many other languages present number categories of singular or plural. Some languages also have a dual, trial and paucal number or other arrangements.

The word "number" is also used in linguistics to describe the distinction between certain grammatical aspects that indicate the number of times an event occurs, such as the semelfactive aspect, the iterative aspect, etc. For that use of the term, see "Grammatical aspect".

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.

Counterfactual conditionals (also contrafactual, subjunctive or X-marked) are conditional sentences which discuss what would have been true under different circumstances, e.g. "If Peter believed in ghosts, he would be afraid to be here." Counterfactuals are contrasted with indicatives, which are generally restricted to discussing open possibilities. Counterfactuals are characterized grammatically by their use of fake tense morphology, which some languages use in combination with other kinds of morphology including aspect and mood.

Counterfactuals are one of the most studied phenomena in philosophical logic, formal semantics, and philosophy of language. They were first discussed as a problem for the material conditional analysis of conditionals, which treats them all as trivially true. Starting in the 1960s, philosophers and linguists developed the now-classic possible world approach, in which a counterfactual's truth hinges on its consequent holding at certain possible worlds where its antecedent holds. More recent formal analyses have treated them using tools such as causal models and dynamic semantics. Other research has addressed their metaphysical, psychological, and grammatical underpinnings, while applying some of the resultant insights to fields including history, marketing, and epidemiology.

A conditional sentence is a sentence in a natural language that expresses that one thing is contingent on another, e.g., "If it rains, the picnic will be cancelled." They are so called because the impact of the sentence’s main clause is conditional on a subordinate clause. A full conditional thus contains two clauses: the subordinate clause, called the antecedent (or protasis or if-clause), which expresses the condition, and the main clause, called the consequent (or apodosis or then-clause) expressing the result.

To form conditional sentences, languages use a variety of grammatical forms and constructions. The forms of verbs used in the antecedent and consequent are often subject to particular rules as regards their tense, aspect, and mood. Many languages have a specialized type of verb form called the conditional mood – broadly equivalent in meaning to the English "would (do something)" – for use in some types of conditional sentences.

A verb is a word that generally conveys an action (bring, read, walk, run, learn), an occurrence (happen, become), or a state of being (be, exist, stand). In the usual description of English, the basic form, with or without the particle to, is the infinitive. In many languages, verbs are inflected (modified in form) to encode tense, aspect, mood, and voice. A verb may also agree with the person, gender or number of some of its arguments, such as its subject, or object. In English, three tenses exist: present, to indicate that an action is being carried out; past, to indicate that an action has been done; and future, to indicate that an action will be done, expressed with the auxiliary verb will or shall.

In linguistics, conjugation (/ˌkɒndʒʊˈɡeɪʃən/ con-juu-GAY-shən) is the creation of derived forms of a verb from its principal parts by inflection (alteration of form according to rules of grammar). For instance, the verb break can be conjugated to form the words break, breaks, and broke. While English has a relatively simple conjugation, other languages such as French and Arabic or Spanish are more complex, with each verb having dozens of conjugated forms. Some languages such as Georgian and Basque (some verbs only) have highly complex conjugation systems with hundreds of possible conjugations for every verb.

Verbs may inflect for grammatical categories such as person, number, gender, case, tense, aspect, mood, voice, possession, definiteness, politeness, causativity, clusivity, interrogatives, transitivity, valency, polarity, telicity, volition, mirativity, evidentiality, animacy, associativity, pluractionality, and reciprocity. Verbs may also be affected by agreement, polypersonal agreement, incorporation, noun class, noun classifiers, and verb classifiers. Agglutinative and polysynthetic languages tend to have the most complex conjugations, although some fusional languages such as Archi can also have extremely complex conjugation. Typically the principal parts are the root and/or several modifications of it (stems). All the different forms of the same verb constitute a lexeme, and the canonical form of the verb that is conventionally used to represent that lexeme (as seen in dictionary entries) is called a lemma.

Jeju (Jeju: 제줏말; Jeju RR: Jejunmal, or Korean: 제주어; RR: Jejueo, or 제주말; Jejumal), often called Jejueo or Jejuan in English-language scholarship, is a Koreanic language originally from Jeju Island, South Korea. It is not mutually intelligible with mainland Korean dialects. While it was historically considered a divergent Jeju dialect of the Korean language, it is increasingly referred to as a separate language in its own right. It is declining in usage and was classified by UNESCO in 2010 as critically endangered, the highest level of language endangerment possible. Revitalization efforts are ongoing.

The consonants of Jeju are similar to those of the Seoul dialect of Korean, but Jeju has a larger and more conservative vowel inventory. Jeju is a head-final, agglutinative, suffixing language, like Korean. Nouns are followed by particles that may function as case markers. Verbs inflect for tense, aspect, mood, evidentiality, relative social status, formality, and other grammatical information. Korean and Jeju differ significantly in their verbal paradigms. For instance, the continuative aspect marker of Jeju and the mood or aspect distinction of many Jeju connective suffixes are absent in Korean. Most of the Jeju lexicon is Koreanic, and the language preserves many Middle Korean features and words now lost in Standard Korean. Jeju may also have a Peninsular Japonic substratum, but this argument has been disputed.

In linguistics, a grammatical category or grammatical feature is a property of items within the grammar of a language. Within each category there are two or more possible values (sometimes called grammemes), which are normally mutually exclusive. Frequently encountered grammatical categories include:

• Case, varying according to the relations between the participants in an action (e.g. subject, object, possession, direction, accompaniment etc.).
• Noun classes, such as gender, animacy, and so on.
• Number, varying according to the number of things (e.g. singular or plural).
• Tense, varying according to when an action takes place (e.g. present, past or future).
• Aspect, varying according to the state of an action in relation to time (e.g. completed, ongoing, repeated, habitual etc.).
• Mood and modality, varying according to the speaker's attitude towards an action and its relation to reality (e.g. statement of fact, hypothetical, questioning, ordering, suggesting etc.).
• Voice, varying according to the role taken by each participant in an action (e.g. active or passive).

Although the use of terms varies from author to author, a distinction should be made between grammatical categories and lexical categories. Lexical categories (considered syntactic categories) largely correspond to the parts of speech of traditional grammar, and refer to nouns, adjectives, etc.

Latin is a heavily inflected language with largely free word order. Nouns are inflected for number and case; pronouns and adjectives (including participles) are inflected for number, case, and gender; and verbs are inflected for person, number, tense, aspect, voice, and mood. The inflections are often changes in the ending of a word, but can be more complicated, especially with verbs.

Thus verbs can take any of over 100 different endings to express different meanings, for example regō "I rule", regor "I am ruled", regere "to rule", regī "to be ruled". Most verbal forms consist of a single word, but some tenses are formed from part of the verb sum "I am" added to a participle; for example, ductus sum "I was led" or ductūrus est "he is going to lead".

In linguistics, grammatical mood is a grammatical feature of verbs, used for signaling modality. In other words, it is the use of verbal inflections that allow speakers to express their attitude toward what they are saying (for example, a statement of fact, of desire, of command, etc.). The term is also used more broadly to describe the syntactic expression of modality – that is, the use of verb phrases that do not involve inflection of the verb itself.

Mood is distinct from grammatical tense or grammatical aspect, although the same word patterns are used for expressing more than one of these meanings at the same time in many languages, including English and most other modern Indo-European languages. (See tense–aspect–mood for a discussion of this.)

In linguistics, the aspect of a verb is a grammatical category that defines the temporal flow (or lack thereof) in a given action, event, or state. As its name suggests, the habitual aspect (abbreviated HAB), not to be confused with iterative aspect or frequentative aspect, specifies an action as occurring habitually: the subject performs the action usually, ordinarily, or customarily. As such, the habitual aspect provides structural information on the nature of the subject referent, "John smokes" being interpretable as "John is a smoker", "Enjoh habitually gets up early in the morning" as "Enjoh is an early bird". The habitual aspect is a type of imperfective aspect, which does not depict an event as a single entity viewed only as a whole but instead specifies something about its internal temporal structure.

Östen Dahl found that the habitual past, the most common tense context for the habitual, occurred in only seven of 60 languages sampled, including English. Especially in Turkic languages such as Azerbaijani and Turkish, he found that the habitual can occur in combination with the predictive mood.