Grammar

A pronoun is a member of a grammatical category whose uses commonly occupy nominal positions while their interpretation is recovered from context. A previous noun phrase can supply that context, but is not required: I can identify the current speaker without repeating an earlier name.^[ref]

Consider The robot moved beside the box. It stopped. Under a stipulated reading where both objects are possible referents, the spelling it alone does not select one. Grammatical number and syntax can constrain the possibilities while leaving a contextual decision unresolved. The category of the expression and the identity of its referent are distinct annotation questions.

The border with determiners also depends on the adopted scheme. Universal Dependencies documents PRON and DET using characteristic distribution and language-specific conventions. An explicit inventory helps compare text corpus annotations without assuming that a familiar label always covers exactly the same words in every language.

Grammatical voice concerns how a construction relates an event's participants to grammatical positions such as subject and object. Active voice and passive voice provide a familiar contrast, but the categories recognized across languages are not limited to that pair.^[ref]

In The mechanic repairs the pump, the mechanic is the subject. In The pump is repaired by the mechanic, the pump occupies that relation while the mechanic is expressed differently. Both can describe the same repair. Changing is repaired to was repaired instead changes grammatical tense while retaining passive voice.

A structural account can therefore hold the participants and event approximately fixed while varying their expression. Separating grammatical voice, grammatical tense and thematic roles prevents a parser or an experiment from treating those dimensions as interchangeable. It also makes the claimed invariants and changes in a comparison explicit.

Active voice is the grammatical voice of constructions such as The technician opened the valve, where the actor is expressed as subject. It contrasts with a corresponding passive voice construction, The valve was opened by the technician, in which that participant is expressed differently.^[ref]

The contrast holds the described event fixed while changing grammatical organization. In the first example, the valve is the object; in the second, it occupies the subject position. The actor's presence in a by-phrase does not make that phrase the subject.

Separating voice from other features avoids a common classification error. The technician did not open the valve remains active even though it denies that an opening occurred. Likewise, changing opened to opens can change grammatical tense without changing grammatical voice. A grammatical analysis should identify the construction and its participant relationships, rather than infer voice from whether the sentence sounds energetic or describes a completed action.

A determiner is a grammatical category whose members help specify the reference of a noun phrase in context. They can signal distinctions such as definite versus indefinite reference, proximity or quantity. Their contribution differs from the descriptive property supplied by a typical adjective.^[ref]

Compare a red box, the red box and this red box. The descriptive words can remain fixed while the expressions impose different expectations about identifying the referent. In a display with several red boxes, pointing can help interpret this, while an earlier mention can help establish the intended referent of the.

Classification also requires a stated scheme. Universal Dependencies includes articles such as a and the under DET, but uses a separate numerical label for cardinal numbers. A familiar broad description like “a word before a noun” is therefore too weak to reproduce the intended linguistic annotation.

A part of speech is a grammatical word category identified by patterns of distribution, combination and, where relevant, inflection. Categories such as noun, verb and adjective help describe what an expression can do in a construction. Meaning is evidence, but a rule equating a category with one broad kind of meaning is insufficient.

For example, record is a noun in the record and a verb in record the result. The same spelling can therefore require different labels when its context changes. A computational annotation scheme must state whether it assigns categories to lexical entries, individual occurrences or both.^[ref]

Universal Dependencies separates a broad part of speech label from additional grammatical features. Two forms can share the label NOUN while differing in grammatical number. Keeping category and features distinct makes an analysis of a text corpus reproducible without multiplying category labels for every possible form.

Grammatical agreement is a formal relationship in which the form of one linguistic element requires a corresponding form of another. Grammatical number can participate in this relationship, but the features expressed and the elements involved vary among languages. Agreement is a constraint on connected grammatical elements, rather than a requirement that adjacent words merely resemble each other.^[ref]

Compare The key to the cabinets is missing with The keys to the cabinet are missing. In these English examples, the verb form tracks the number of the subject's head noun, not the closest noun. An explicit model can assign Number=Sing to key and require the corresponding agreement form is. Changing the embedded noun cabinet to cabinets leaves that requirement intact. Such contrasts provide testable predictions for a proposed syntax and show why a rule based only on the nearest preceding word fails.

Grammatical number is a grammatical category expressing count-related distinctions, commonly singular and plural, through word forms or grammatical agreement. It is a feature of a linguistic expression, not simply the numerical size of the thing being described. Its categories do not always correspond directly to the count of real-world referents.^[ref]

The contrast boat/boats marks singular versus plural on a noun. Yet These scissors are blunt can describe one tool while using plural forms and plural grammatical agreement. Conversely, a committee can denote several people through a singular noun. An annotation should therefore record the grammatical feature separately from an investigator's count of objects. Some languages distinguish a dual category for exactly two, showing that the inventory of number categories is itself an empirical question.^[ref]

An adjective is a part of speech characteristically used to express properties and modify nouns. It can also occur in predicative constructions, as in The cube is red. Its classification depends on its grammatical behavior, beyond whether its meaning sounds descriptive.^[ref]

In an original simple formal semantics, let red objects form $R=\{1,2\}$ and cubes form $C=\{2,3\}$. The expression red cube can denote the intersection $R\cap C=\{2\}$. This illustrates how an adjective can contribute a property to a noun phrase, while leaving the grammatical classification distinct from that particular semantic rule.

Modification alone is insufficient evidence for adjective status. In the Universal Dependencies scheme, a noun used to modify another noun in a compound remains tagged as a noun. Clear category criteria make linguistic annotation reproducible instead of treating every modifier as the same class.

A verb is a part of speech that commonly organizes a clause, specifying relationships among its participants and contributing an event or state description. Forms of a verb may express grammatical tense, grammatical aspect or grammatical agreement, though the mechanisms differ across languages.^[ref]

Compare Rin sleeps with Rin opens the box. The second construction contains an object in addition to its subject; knowing a verb includes knowing how it combines with other expressions. Calling verbs “action words” misses examples such as know, which describes a state.

An annotation scheme must also define its boundaries. Universal Dependencies assigns main verbs the label VERB while distinguishing auxiliary uses with AUX. Thus a traditional grammatical description and a particular computational tag inventory need not draw every boundary identically. Stating the scheme makes category counts in a text corpus interpretable.

A noun is a part of speech whose members commonly name entities or concepts and head noun phrases. Meanings alone do not supply a complete classification: a noun can name an event or property as readily as a physical object. Distribution and inflection provide additional grammatical evidence.^[ref]

For example, explosion names an event, but behaves as a noun in the explosion and two explosions. Its connection with an event does not make it a verb; compare The shell exploded. Likewise, redness is a noun even though it names a property associated with the adjective red.

In Universal Dependencies, the tag NOUN is reserved for common nouns, with PROPN used for proper nouns. That distinction matters when reproducing an analysis: a count of every traditionally named noun is not necessarily a count of only tokens tagged NOUN.

A proper noun is a noun used as a name, or as a nominal part of a name, for a specific individual, place or entity. Its naming function differs from the classifying use of a common noun. Capitalization can be a writing convention associated with that distinction, but is not by itself a universal grammatical test.^[ref]

In the original example Dara is a teacher, Dara functions as a name while teacher classifies the person. By contrast, Teacher arrived late can capitalize a common noun merely because it begins the written sentence. A classifier using only the initial capital would confuse these roles.

The Universal Dependencies code PROPN also does not automatically apply to every component of an arbitrarily long name. The scheme retains the appropriate categories for many component words in phrase-like names. Explicit criteria therefore matter when counting names or evaluating linguistic annotation.

A common noun is a noun used to classify an entity or concept rather than to provide an individual name. It can describe a concrete thing, an event or an abstraction. The contrast with a proper noun concerns grammatical use, beyond whether the referent happens to be unique in a particular conversation.^[ref]

In the village teacher, teacher remains a common noun even if the village has only one teacher. In two explosions, explosions names events and shows plural grammatical number; an event meaning does not make the form a verb. These examples separate semantic reference from lexical category.

For a text corpus using Universal Dependencies, the tag NOUN identifies this category while PROPN identifies proper nouns. Sentence-initial capitalization is therefore inadequate as the sole labeling rule. A repeatable annotation procedure considers context and the scheme's category definitions.

Grammatical aspect presents a temporal view of an event or state, for example as ongoing or as a whole. It concerns how the event is viewed, whereas grammatical tense concerns its relation to a temporal reference point. Affixes and auxiliary constructions can express aspectual distinctions.^[ref]

Compare “The train arrived” with “The train was arriving”. Both locate the situation in the past, but the second presents an unfolding situation and does not by itself assert a completed arrival. Comparing “is arriving” with “was arriving” instead changes tense while retaining the progressive construction. Such contrasts help isolate which part of an interpretation comes from each grammatical choice. A formal semantics can encode those differences explicitly, rather than treating every temporal expression as the same kind of label.

Grammatical tense locates an event or state relative to a temporal reference point, commonly the time of speaking. A language may mark it through verb forms or grammatical constructions. Temporal reference itself is broader: a time expression can convey when something happens without being a tense marker.^[ref]

In the simple past statement “The train arrived”, the arrival precedes the speech time. Writing event time $E$ and speech time $S$, this simple relation is $E<S$. “The train was arriving” also has past tense, but changes grammatical aspect by presenting the arrival as unfolding. Thus the two categories answer different questions. A precise model states its reference point and interpretation; identifying a past-looking ending alone does not settle every temporal relation in a complex utterance.