A Dictionary of Linguistics and Phonetics David Crystal

L
labelling (n.) A term in grammatical analysis for the explicit marking of the
parts or stages in a structural analysis of a sentence. For example, the main
structural divisions in the sentence People ran can be signalled using such
methods as bracketing or a tree diagram, e.g. [[people] [ran]]; but this analysis
is made more meaningful if a structural description is added (assigned)
to the brackets through the use of labels, e.g. [[people] N [ran] V ] S where N = noun,
V = verb and S = sentence. Such a convention is known as a labelled bracketing.
In a tree diagram nodes can be labelled similarly.
labial (adj./n.) A general term in the phonetic classification of speech sounds
on the basis of their place of articulation: it refers to active use of one lip (as
in labio-dental sounds, such as [f]) or both lips (as in bilabial consonants,
such as [b], or rounded vowels, such as [u]). In an empty sense, all oral sounds
are labial, in that the airflow has to pass through the lips: the important qualification
in the above definition is that the lips are actively involved. From a position of
rest, there must be a marked movement to qualify as a labial sound (‘a labial’),
and it is lip-rounding which is the most common and noticeable feature.
Similarly, labialization is a general term referring to a secondary articulation
involving any noticeable lip-rounding, as in the initial [k] of coop, or sh-
[à] of shoe, which are here labialized, because of the influence of the labialization
in the following vowel [u]. Labialization is applied both to cases where the
lip-rounding is an essential feature of a sound’s identity, as in [u], and to cases
where the lip-rounding is found only in specific contexts, as in the [k] example
above – in kill, there is no labialization. The diacritic for labialization is
[ w ], underneath the main symbol, but a raised [ w ] is often used. The term has
developed a special status in phonological theory, especially in various nonlinear
models. For example, in articulator-based feature theory, it refers
to a single-valued node involving the lips as an active articulator. In constriction-based
models, it is defined as a constriction formed by the lower lip. See
also -ise/ize.
labio-dental (adj./n.) A term used in the phonetic classification of speech
sounds on the basis of their place of articulation: it refers to a sound in
which one lip is actively in contact with the teeth. The usual mode of operation
A Dictionary of Linguistics and Phonetics 6th Edition. David Crystal
© 2008 David Crystal. ISBN: 978-1-405-15296-9