Page 84 - Edited - Webster HEAD AND NECK - part 2-Merge PDF

HN 276

Articulation. The sounds so produced are chopped up into many and various subsets principally by operation of
the tongue (motor supply, hypoglossal nerves) against the palate, alveolar margins and teeth; the lower jaw (motor
- trigeminal nerves); lips (motor - facial nerves); and the soft palate (motor - vagus nerves). Even the larynx
can be used in articulation: the feature of pronunciation known as the “glottal stop” - as in an emphatic hard c in
more or less “received pronunciation” (“You must aCt!”); or, in that most unappealing of accents generally known
as “Estuarine”, the pronunciation of words like “butter” (“bu-er”) or even “glottal” (“glo-al”). Production of these
sounds involves almost instantaneous closing and opening of the glottis . In as far as speech involves tonal variety,
2
the pharynx, soft palate and the pharyngeal tongue are also involved. (For example, inability to oppose the soft
palate to the pharynx to shut off the nasal cavity leads to indistinct pronunciation of consonants - not only k or
hard g, but also t and d. This is hypernasal speech. Inability to open the palate produces hyponasal speech, which
sounds “adenoidal”.) All relevant motor neurons are in the hindbrain.

Failure of articulation is dysarthria, best identified as slurred speech: it occurs in hypoglossal palsy
(including stroke), facial palsy, cerebellar disease, and alcohol intoxication. Language processes and phonation
remain normal - it is the execution which is impairtG. Sensory feedback is provided by the trigeminal nerves -
its importance will be apparent to anyone who has had a local anaesthetic block for dental surgery, when a minor
dysarthria becomes evident - especially in inferior dental block, which anaesthetises the lower lip and
corresponding half of the tongue without paralysing them

It is important to realise that articulation is a learned skill which some children fail to acquire adequately:
although their vocabulary increases, their speech remains intelligible only to close family, since they are unable
to advance much beyond the trial articulations of early infancy. Such children need , early speech therapy. During
speaking ( or singing) the stapedius and tensor tympani muscles (Vllth and Vth nerves) of the middle ear contract,
apparently to minimise airborne feedback.

The language areas of the cerebral cortex manipulate the above mechanism to produce intelligible
3
speech and song. The necessary respiratory control is emphasised by consideration of singing

K.E.W

2 Note Mr Brian Sewell, reacting to the news of the continuing spread of "Estuarine", remarked "I couldn't possibly make love to a woman who spoke with a
glottal stop". Judging by the collective talents of "Eastenders", he has a point.
3 NOTE The variable resonators of the pharynx and mouth are deliberately manipulated by singers to increase the richness of the sounds they produce. One of
these manoeuvres induces vocal vibrato. Interestingly, its frequency is virtually that used by string players, i.e. ~5 Hz - see Neuro notes, Vol. I, p.129
Note: 81 - but its band-width is greater - approximately ± ¼ tone as opposed to ± 1/8 tone. Used to excess (as by many singers of the "ballade"
variety) it sounds terrible. Pop "singers" of e.g. the "Group" variety, grunt, howl, shriek, shout and squeak, but don't sing anyway.

\NewCMedPhysSc\23 HN 275 Vocalisation.