Prosody and Language
by Rebecca Martin
Prosody is the aspect of language that goes beyond
verbal communication; it involves communication without
words. Prosody involves the intonation (voice-pitch
fluctuations), stress, timing , and rhythm of utterances.
"By altering the way we say the same sentence we can
change it from a simple statement to a question and then
to a command (Ellis & Young 252)". Disturbances in
prosody can also change the meaning of compound nouns
[example: "green HOUSE" vs. "GREENhouse" (Ellis &
Young 253)]. Affective prosody is the aspect of
language that delivers the emotion behind words.
Affective prosody can change the intention of a
statement's meaning by expressing it as happy, sad,
angry, or confused. Pertinent issues involving prosody
include its role in language acquisition, types of
aprosodia, hemispherical differences in prosodic
disruption, causes of prosodic impairment, and
possibilities for rehabilitation of prosodic
disturbances.
Prosodic structure is used to organize a
representation of a sentence in working memory while
comprehension takes place. Two characteristics of
prosody greatly aid language comprehension. First of
all, as a speaker delivers a sentence, it must fit within
the limits of the listener's processing system used to
understand auditory information; prosodic structure works
within these limits. Prosodic information also helps
compensate for the lack of syntactic structure when
auditory information is not syntactically well-formed.
Swerts & Geluykens (1993) attempted to establish the
importance of prosody to the listener in language
comprehension. The main focus of the study was to
determine the effectiveness of prosodic cues ( voice
intonation and pause duration) to identify the end of a
clause in a sentence. A set of verbal instructions was
recorded and then filtered to retain prosodic cues, but
make words unintelligible. Three versions of these
filtered instructions were then presented to subjects;
one version contained the original prosody, one had the
same voice fluctuations and a constant pause duration,
and one had the same pause duration but was presented
with a monotonous pitch. The findings suggested that
although they are helpful, both aspects of prosody are
not necessary. Speech melody does contribute to
communication, and use of pausal structures is enhanced
by melodic flow.
Other studies (Gerken et al., 1994; Mandel et at.,
1994) have attempted to determine the role of prosody in
language acquisition. (Gerken et al., 1994) established
that while prosody does offer cues to some syntactic
structure, syntactic structure is not necessarily defined
by prosody. In this study, infants correctly identified
prosodic boundaries when alterations in prosodic cues
occurred together. Altered versions of natural speech
were presented to 9-month-olds to determine their
recognition of prosodic cues. Presented speech samples
exhibited a decrease of natural voice pitch and an
decreased syllable length or a decreased pitch and a
decrease in syllable duration. Infants showed better
performance in identifying prosodic boundaries by
decreases in voice pitch and longer syllable duration; as
opposed to a decrease in voice pitch and an increase in
duration.
In an extension of the previous study, (Mandel et
al., 1994), found that infants are able to retain
phonetic information when it is presented in single
prosodic units in comparison with being spoken in a list.
Sentential prosody also benefits the early learner of a
language by enhancing retention with syntactically well-
formed sentences. Implications of the effect of prosody
on language acquisition in this study are relatively
significant. Infants apparently have the ability to
exploit the available prosodic cues to help organize and
encode what they hear. Prosody can also serve as a basis
for later syntactic acquisition. Prosody is also helpful
in keeping together and retaining information units, and
aiding in identifying linguistic units.
In research of infarcts in the right hemisphere
(Bradvik, et al., 1995) reported that the right
hemisphere is of importance for identification and
production of several linguistic prosodic qualities of
speech as well as for identification of emotions.
(Trauner, et al., 1995) studied children and young adults
who suffered from early unilateral brain damage. The
group as a whole showed deficits in comprehension and
expression of prosody. Hemispherical differences in
prosodic functions were noticed, however. Individuals
with right hemispherical lesions demonstrated
difficulties in comprehension and expression of affective
and linguistic cues. Those with left hemisphere lesions
showed difficulty primarily in expression of affective
prosody and in receptive and expressive components of
linguistic prosody. (Wolfe & Ross 1987) studied the
effects of left hemiparesis on prosody. Their findings
support the idea that anatomic functional organization of
affective language occurs in the right hemisphere, and
propositional language organized in the left hemisphere.
(Boss, et al., 1996) specified types of affective
prosodic disturbances resulting from right brain injury.
These disturbances of affective prosody language are
termed "aprosodias". This report detailed four types of
aprosodias, including motor, sensory, global, and
transcortical. Motor aprosodia is characterized by
flat, monotonous speech and loss of spontaneous
gesturing. The ability to mimic the emotional tome of
statement is also impaired. Motor aprosodia usually
results from right frontal and anterior-inferior parietal
lobe lesions. Sensory aprosodia is the impaired ability
to understand the mood and/or emotion being conveyed
auditorily, or visually by gestures and facial
expressions. Prosodic repetition is also impaired.
Sensory aprosodia is generally caused by right posterior
temporal and posterior-inferior parietal damage. Global
aprosodia exhibits all of the components of sensory and
motor aprosodia. In global aprosodia, prosody, gestures,
pantomime and facial expressions are neither comprehended
nor exhibited. This results in a strikingly flat
personal affect. This aprosodia is caused by a
perisylvan insult to frontal, parietal, and temporal
areas of the cortex. Transcortical aprosodia is the
impairment of comprehension of prosody. However,
gesturing, emotion, facial expression, prosody, and
repetition of pragmatic (nonverbal) components of
language are unaffected. Disturbances are usually caused
by right anterior and inferior temporal lobe injury.
In diagnosing prosodic disturbances as damage to
prosodic areas of the brain, it is important to realize
that other injuries to other areas of the brain can cause
prosodic disturbances. Prosodic disturbances can be
caused by damage to many areas of the Central Nervous
System. This can involve the respiratory, laryngeal,
velopharyngeal and articulatory systems. Damage to any
of these areas can manifest as prosodic disturbances.
Physiological examination of the brain in necessary to
determine actual damage to prosody.
Some causes of prosodic disturbance not involving
injury are those organic brain disorders that can cause
dementia and various other disorders impairing
communication. Parkinson's disease is one of these
disorders. PD patients experience disturbances in
prosody; emotional and linguistic and ability to
discriminate word meaning based on stress cues. They
also have difficulty with production of question
intonation, stress and the expression of emotion through
prosody. Schizophrenics are very bad with comprehension
and expression of emotional prosody. This group performs
significantly poorly with expression of emotional
prosody; which is similar to right hemisphere injury.
Alzheimer's disease can also cause disturbances in
production, repetition, and comprehension of emotional
prosody. Deficits in comprehension of emotional prosody
appear relatively early in the course of AD and are
relatively resistant to further decline throughout the
mild and moderate stages of the disease. Moderately
demented AD patients were also significantly impaired in
their ability to produce and repeat emotional prosody.
Mildly demented AD patients didn't show these
impairments; these functions are preserved in the early
stages of the disease. Significant impairment emerges by
the time the patient reaches the middle stages of this
disease. Mildly demented AD patients exhibited mildly
impaired prosodic comprehension; moderately demented
patients, however, show relative weakness in emotional
prosody production, and strength in emotional prosody
comprehension.
In conclusion, many who suffer from prosodic
disturbances can undergo therapy to greatly improve their
dysfunctional state. Stringer (1996) treated the
prosodic disturbance of R.P.; a car accident victim with
a right-sided posterior, subdural haematoma with
occipital and nasal bone fractures. Disturbances
included minimal changes in facial expression and a
monotonous vocal pattern. The goal of the pitch
biofeedback therapy was to increase affective expression.
Although R.P. was not returned to full pre-injury
affective capacity, she did greatly improve her affective
expression, and improvements remained stable for two
months after treatment. Although prosodic disturbance
is detrimental to communication and therefore, much study
has been done on the subject, more research is necessary
to determine the localization of damage that causes
prosodic disturbance.
Works Cited
Boss, B. J. (1996). Pragmatics: Right brain
communication. Axon, 17 (4), 81-85.
Bradvik, B., Dravins, C., Holtas, S., Rosen, I., Ryding,
E. & Ingvar, D.H. (1991). Disturbances in speech
prosody following right hemisphere infarcts. Acta
Neurologica Scandinavica, 84, 114-126
Ellis, A.W., & Young, A.W. (1993). Human Cognitive
Neuropsychology. London: Lawrence Earlbaum
Associates.
Gerken, L., Jusczyk, P.W., & Mandel, D.R. (1994). When
prosody fails to cue syntactic structure: 9-month-
olds' sensitivity to phonological versus syntactic
phrases. Cognition, 51, 237-265.
Mandel, D.R., Jusczyk, P.W. & Kemler Nelson, D.G.
(1994). Does sentential prosody help infants
organize and remember speech information.
Cognition, 53, 155-180.
Stringer, A.Y. (1996). Treatment of motor aprosodia with
pitch biofeedback and expression modelling. Brain
Injury, 10 (8), 583-590.
Swerts, M. & Geluykens, R. (1993). The prosody of
information units in spontaneous monologue.
Phonetica, 50, 189-196.
Trauner, D.A., Ballantyne, A., Friedland, S., & Chase, C.
(1996). Disorders of affective and linguistic
prosody in children with early unilateral brain
damage. Annals of Neurology, 39 (3), 361-367.
Wolfe, G.I. & Ross, E.D. (1987). Sensory aprosodia with
left hemiparesis from subcortical infarction.
Archives of Neurology, 44, 668-670.
Return to the Project Table of
Contents
Go back to the beginning
Copyright © 1997, Dr. John M. Morgan, All rights
reserved - This page last edited March 17, 1997
If you have any feedback for the author, E-mail
me
