A Dictionary of Linguistics and Phonetics David Crystal

imperfective 237
image schema A type of basic conceptual structure identified in cognitive
semantics. Schemas such as Path and Container are held to be prelinguistic
structures based on bodily experience and which help to shape the form of
linguistic categories. They are used to describe, for example, the semantics of
spatial, temporal and aspectual expressions. See also schema.
imitation (n.) An application of the general sense of this term to language
acquisition, where it refers to children’s behaviour in copying the language
they hear around them. The importance of the notion is twofold. First, it has
been shown that imitation cannot by itself account for the facts of language
development (despite a popular view to the contrary – that children learn
language by imitating their parents): forms such as *mouses and *wented, and
sentences such as *Me not like that, show that some internal process of construction
is taking place. Second, the skills children show when they are actually
imitating are often different, in important aspects, from those they display
in spontaneous speech production, or in comprehension. The relationship
between imitation, production and comprehension has been a major focus of
experimental and descriptive interest in acquisition studies.
immediate constituent (IC) A term used in grammatical analysis to refer to
the major divisions that can be made within a syntactic construction, at any
level. For example, in analysing the sentence The boy is walking, the immediate
constituents would be the boy and is walking. These in turn can be analysed
into immediate constituents (the + boy, is + walking), and the process continues
until irreducible constituents are reached. The whole procedure is known as
immediate-constituent analysis (or ‘constituent analysis’), and was a major
feature of Bloomfieldian structuralist linguistics.
immediate dominance (1) A term used in generative linguistics for a type
of relationship between nodes in a phrase-marker: a node A immediately
dominates a node B if and only if (a) A dominates B, and (b) there is no node
C such that it also dominates B and is dominated by A.
(2) An immediate dominance (ID) rule is a type of rule in generalized phrasestructure
grammar of the form X ⇒ Y, Z. It specifies that X can dominate Y
and Z but does not specify the relative order of Y and Z. Together with linear
precedence rules and various general principles, ID rules generate phrasemarkers
of the classical type.
imperative (adj./n.) (imp, imper, IMPER) A term used in the grammatical
classification of sentence types, and usually seen in contrast to indicative,
interrogative, etc. An imperative usage (‘an imperative’) refers to verb forms
or sentence/clause types typically used in the expression of commands, e.g.
Go away!
imperfective (adj./n.) A term used in the grammatical analysis of aspect,
referring to those forms of the verb which mark the way in which the internal
time structure of a situation is viewed. Imperfective forms (or ‘imperfectives’)
contrast with perfective forms, where the situation is seen as a whole, regardless
of the time contrasts it may contain. The contrast is well recognized in the
grammar of Slavic languages.