A Dictionary of Linguistics and Phonetics David Crystal

238 imperfect tense
imperfect tense (imp, imperf, impf, IMPF) In grammar, a tense form used in
some languages to express such meanings as duration or continuity in past time.
Latin is an example of a language which had an imperfect tense: amabam ‘I was
loving/used to love’.
impersonal (adj.)
see person
implicational scaling A model of language variation which aims to account
for the differential spread of changes in a population. Individual variation
is represented as an alternation between old and new rules, and differences
between individuals are viewed as differences in rule inventories. An implicational
table is used to display the spread of rules throughout a population. The approach
contrasts with the variable rule model, in which variability is a property of the
rules themselves.
implicational universal
see universal
implicature (n.) A term derived from the work of the philosopher H. P. Grice
(1913–88) and now frequently used in linguistics as part of the study of
conversational structure. Conversational implicatures refer to the implications
which can be deduced from the form of an utterance, on the basis of certain
co-operative principles which govern the efficiency and normal acceptability
of conversations, as when the sentence There’s some chalk on the floor is taken
to mean ‘you ought to pick it up’; they contrast with explicatures, which are
the propositions that are explictly communicated (the fact that the chalk is on
the floor, in this example). Several types of implicature have been discussed,
in the context of the relationship between language and logical expression, and
of the conditions which affect the appropriateness of utterances. In particular,
implicatures have been classified into generalized and particularized types – the
former not being restricted to a particular context; the latter requiring a specific
context. Also, a contrast has been drawn between conversational (or nonconventional)
implicatures, which are inferences calculated on the basis of the
maxims of conversation, and conventional implicatures, which are not derived
from these principles but simply attached by convention to particular expressions.
Examples of the latter which have been suggested include utterance-initial
oh, the use of therefore, even and yet, and sequences of the type He is an
Englishman; therefore he is brave. However, relatively little detailed linguistic
investigation has yet taken place into these matters, and several of the proposals
are controversial.
implicit argument
see argument
implosive (adj./n.) A term used in the phonetic classification of consonant
sounds on the basis of their manner of articulation: it refers to the series of
plosive sounds it is possible to make using an airstream mechanism involving
an inwards movement of air in the mouth (an ingressive airstream). A
complete closure is made in the mouth, as with any plosive sound, but the air
behind the closure is not compressed, ready for outwards release; instead, a
downwards movement of the larynx takes place, and the air inside the mouth