Chapter 7
Beyond Segments: How Children
Acquire Prosody
Margaret Kehoe
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Introduction
• Prosody plays a crucial role in language development
• Infants are sensitive to prosodic characteristics of language even before
birth
• Interest in prosody has surged since the 1980’s and thrived with the arrival
of widely accessible acoustic analysis software
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–
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Nonlinear phonology
Autosegmental phonology
Metrical phonology
Prosodic phonology
• The aim of this chapter is to give a research-based overview
– Early perceptual and productive prosody
• Stress
• Timing
• Intonation
– Atypical prosody in special populations
• Autism spectrum disorder
• Childhood apraxia of speech
• Language impairment
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Definition of Prosody: General Aspects
Sidebar 7.1 The Prosody Elephant
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Definition of Prosody: Functions
and Effects
Figure 7.1 Functions and effects of prosody
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Definition of Prosody: Components
• Three acoustic dimensions combine to create different prosodic
systems:
– Fundamental frequency (perceived as pitch)
– Amplitude or intensity (perceived as loudness)
– Duration (perceived as length)
• Stress: stressed syllables are longer, louder, and/or higher-pitched
than unstressed ones
• Timing: syllable durations; pause durations
• Phrase-final lengthening: the final syllable in an utterance is longer
than the preceding ones
• Rhythm: pattern of stressed and unstressed syllables in utterances
• Intonation: pattern of fundamental frequency across words,
phrases, and entire utterances
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Figure 7.2 Acoustic display, including time
waveform, spectrogram, and pitch contour of the
word “Puppe” [ˈpʊpə] produced by a Germanspeaking girl, aged 2;0.
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Figure 7.3 Acoustic display, including time
waveform, spectrogram, and pitch contour of the
word “Puppe” [ˈpʊpə] produced by a Germanspeaking girl, aged 2;0, with rising intonation.
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Figure 7.4 The prosodic hierarchy
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Additional Terminology
• Foot
– Trochee (“picture,” “little,” German “Puppe”)
– Iamb (“guitar,” “alone,” German “kaputt”)
(1) Headedness of feet
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• Prosodic patterns in different languages
– Stress-timed: syllable durations can vary; intervals
between stressed syllables can contain variable
numbers of unstressed syllables. Sounds like Morse
code.
• Examples: English, German
– Syllable-timed: syllable durations are fairly uniform.
Sounds like a machine gun.
• Examples: Italian, French
– Mora-timed: syllable durations depend on the number
of moras (unit of syllable weight)
• Example: Japanese
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Prosodic Development:
Perception
• Newborns can discriminate between languages based
on just the low-frequency content, thought to reflect
the rhythmic characteristics of languages
• Infants under 4 months are sensitive to lexical stress
and intonation patterns
• Newborns can distinguish between two languages
based on rhythmic characteristics (stress-, syllable-,
mora-timed)
• Infants prefer their own ambient language over other
languages
• Infants prefer the exaggerated prosody of infantdirected speech (“motherese”)
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Sidebar 7.2 Child-Directed Speech
•
•
•
•
•
•
•
•
•
Also referred to as “Motherese”
Short, simple sentences
Frequent repetitions
Words have one or two syllables
Higher pitch
Wider pitch range
Slower rate
Longer pauses
Increased final syllable lengthening
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Sidebar 7.3 The Prosodic
Bootstrapping Hypothesis
• Infants use prosodic information to infer
clausal and phrasal boundaries
– Acoustic properties cue syntactic boundaries
– Infants are sensitive to these properties
– Infants use these cues in the processing of the
speech stream
• Empirical evidence:
– Infants prefer artificial pauses at natural
boundaries, not in the middle of the passage
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Clausal and Phrasal Segmentation
• Clausal and phrasal boundaries are marked by prosodic
features such as heightened stress, changing intonational
contours, pauses, and lengthening
– Clause
• Infants remember speech information better when it is packaged
within a single prosodic unit instead of isolated words (Mandel,
Jusczyk and Kemler Nelson, 1994)
• Infants age 6 months can recognize a word sequence better when it is
part of a well-formed clause instead of consisting of the last word of
one clause and the first word of another (Nazzi, Kemler Nelson,
Jusczyk, and Jusczyk, 2000)
– Phrase
• Infants age 6 months prefer passages containing a familiar
phonological sequence when this sequence consists of a well-formed
phrasal unit, compared to when it corresponds to a syntactic non-unit
(Soderstrom et al., 2003)
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Word Segmentation
• Metrical segmentation strategy
– German- and English-learning infants, age 6 and 9
months, respectively, prefer trochaic feet (strongweak) over iambic ones (weak-strong) (Höhle,
Bijeljac-Babic, Herold, Weissenborn & Nazzi, 2009;
Jusczyk, Cutler & Redanz, 1993)
– At 7.5 months, babies can segment trochaic words
in a stream of speech and at 10.5 months, also
iambic ones (Jusczyk, Houston, and Newsome,
1999)
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Figure 7.5 Timeline of infant perception of prosody
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Production
Prelinguistic and early linguistic period
•Ambient language effects
– The babble productions of English and Swedish infants at age 10 to 18 months
can not be distinguished by a group of expert listeners (Engstrand, Williams &
Lacerda, 2003) – consistent with other studies that have failed to find an
ambient language effect on babble
– However, when rhythmic and intonational aspects are studied, ambient
language effects can be observed
• Newborn cries of German and French infants resemble the ambient language in pitch
contour (Mampe, Friederici, Christophe & Wermke, 2009)
• In reduplicated babble, French infants produce fewer falling intonational contours than
English infants (Whalen, Levitt, & Wang, 1991) and a higher percentage of long final
syllables (Levitt & Wang, 1991)
• During the late babble and early word stages, ambient language effects are controversial
at the 4-word stage (30-minute recording session with 4 different words)
• At the 25-word stage, clear differences in intonational contours can be seen (included
babble and speech) (Vihman, DePaolis and Davis, 1998)
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Sidebar 7.4 Prosodic Regression
• Some researchers have observed that infants
appear to regress in their acquisition of prosody
between age 10 months and the first word period
– More level intonation after acquiring falling tones
(Scollon, 1976)
– Regression in phrase-final lengthening at the onset of
first words (Levitt, 1993).
• Could be due to (Snow & Balog, 2002)
– More focus on segmental development
– Reorganization of prosodic structures from biologically
based to linguistically based
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Pragmatic Differentiation
• Infants use prosodic tools to convey meaning from a very
early age
• Infants 4 to 8 months use falling or level contours for
discomfort cries and rising intonation for requests
(D’Odorico, 1984)
• At 8 to 9 months, different intonation patterns are used for
shared experiences, playing with toys, and cries for
interventions (the latter with higher pitch and rising
intonation) (D’Odorico and Franco, 1991)
• During the 1-word period, more rising tones are used for
requests for interaction and more falling tones for those
not calling for interaction (Halliday, 1975)
• As mean length of utterance (MLU) increases, contextual
effects on prosody become more noticeable
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Pragmatic Context
• Expressing emotion
– Longer duration, higher F0, lower intensity than during
communicative interaction
• Interacting
– Shorter duration, higher F0, more variable F0 than
during investigating
– Rising tones
• Investigating
– Intermediate duration, lower F0, level F0
– Falling tones
(Papaeliou, Minadakis, & Cavouras, 2002; Papaeliou & Trevarthen, 2006)
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Transitional Phase between One- and
Two-Word Utterances
• Successive Single Word Utterances to two-word
utterances: each word has its own
– Primary stress
– Unique intonational contour
– Pause before/after the word
• Two-word utterances
– Integrated intonational contour
– One primary stress
– No pause between the words
• These two utterance types can co-exist for a
while
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• As children progress from one-word to two-word utterances,
they create an intonational contour integrating the two words
• Different ways to realize two-word combinations (Crystal,
1986)
DÀDDY/ — ÈAT/
DÀDDY/ - ÈAT/
DÀDDY/ . ÈAT/
DÀDDY/ÈAT/
daddy ÈAT
DÀDDY eat
DÁDDY/ — ÈAT/
DÁDDY/ - ÈAT/
DÁDDY/ . ÈAT/
DÁDDY/ÈAT/
DÁDDY eat/
DÁDDY ÈAT/
Key
“.”= short pause,
“-” and “—” = pauses of increasing
length
accents above vowels = falling and
rising pitch contours
capitalization indicates stress
“/” = tone units or sense groups
• Different types of word combinations are integrated in
different ways and at different ages (Behrens & Gut, 2005)
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Stress
• Lexical stress studied more intensively than
phrasal stress
• During the early word period, children use all
three parameters that adults use (pitch,
duration, intensity), although there is great
variability among children
• The earliest parameter to be controlled is
pitch, followed by duration, then intensity
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Stress Acquisition and Stress Errors
• Children make more errors on irregular versus
regular stress forms, indicating that metrical
structure and rules guide children’s acquisition of
stress (Fikkert, 1994; Hochberg, 1988)
• Stress errors occur relatively rarely (Kehoe & StoelGammon, 1997; Pollock et al., 1993; Prieto et al.,
2011; Wijnen, Krikhaar, & Den Os, 1994)
• Some children may shift stress to syllables that are
difficult to articulate (e.g., rhotacized vowels)
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(4) Examples of stress errors in English in children aged
2;3 and 2;10 (from Kehoe, 1998; Kehoe & StoelGammon, 1997)
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(5) Examples of stress errors associated with rhotacized
vowels (adapted from Kehoe, 1997, p.404).
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7S1 English-speaking children, aged 2;10, producing “crocodile,” “helicopter,” and
“kangaroo” with correct and shifted stress
7S2 French-speaking boy, aged 2;9, producing bisyllabic words (“cheval ,“ “fantôme“)
7S3 French-speaking girl, aged 1;10, producing bisyllabic words (“biberon,“ “poisson,“
“tortue,“ “assiette“)
7S4 German-speaking girl, aged 2;6, producing bisyllabic words (“Puppe,” “Sonne,”
“Walde”)
7S5 German-speaking boy, aged 2;6, producing bisyllabic words (“Hause,” “Henne”)
7S6 Spanish-speaking boy, aged 2;6, producing bisyllabic words (“barco,” “bota,”
“corto,” “gato,” “grande,” “malo”)
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Phrasal and Contrastive Stress
• Children at the two-word stage are able to use stress to create
contrast and emphasis
(6) Seth using stress to mark new information
(Examples taken from Wieman, 1976, p.286)
Man. BLUE man.
Ball. NICE ball. ORANGE ball.
No sock. BLUE sock.
• From age 2;9 to 4;6, children use contrastive stress to signal new
information (Baltaxe, 1984; Hornby & Hass, 1970)
• More prevalent when referring to subjects than verbs or objects
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Compound Word versus Phrasal Stress
• 2-year-old children can produce correct lexical stress
in compound nouns, but the distinction between
compound and phrasal stress develops later, well
into the school years
(7) Compound vs. Phrasal Stress (Vogel & Raimy, 2002, p.228)
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(8) Examples of compound nouns and noun phrases
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Production vs. Comprehension of
Phrasal and Sentence stress
• By age 4 years, children are competent users
of phrasal and sentence stress
• Their ability to interpret phrasal and sentence
develops later, by 6 years of age
• Asymmetry may relate to methodological
differences
– Comprehension tasks are more complex, e.g.,
disambiguating linguistic structures
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Timing
Rhythm
•Stressed-timed languages have roughly equal intervals between
stressed syllables (e.g., German, English)
•Syllable-timed languages have syllables of roughly equal length (e.g.,
Spanish)
•A better way to quantify syllabic durations:
– In Ramus et al.’s (1999) approach, the duration of vocalic and
consonantal intervals is submitted to three calculations:
• the proportion of vocalic intervals within the sentence (%V),
• the standard deviation of the duration of vocalic intervals (∆V),
• the standard deviation of the duration of consonantal intervals (∆C),
– Low et al. (2000): Pairwise Variability Index: differences in duration in
any two successive pairs of intervals
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• By age 3 or 4, children show the rhythmic
characteristics of their ambient language in
terms of vocalic and consonantal durations
(studies done in German, English, French,
Cantonese)
• Children learning a syllable-timed language
show the rhythmic characteristics of the
ambient language at an earlier age than
children learning a stress-timed language
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Phrase Final Lengthening (PFL)
• The prolongation of the final syllable in a
phrase
• Not clear whether this is a biological
phenomenon or has a linguistic basis
• In a study of children in the one-word stage
(age 1;0 to 1;8), Snow (1994) found that PFL
declined in the middle of the study period and
increased again, closely linked to the
emergence of two-word utterances
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Intonation
• Intonation is the change in F0 across words,
phrases, or longer utterances
• In adult speech, it has many functions
– Affective
– Pragmatic
– Grammatical
• Children as young as 1;6 mark final syllables
with falling tones
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Functional Development of
Intonation
• Do children express pragmatic intent or
emotion in their use of intonation? (Snow &
Balog, 2002)
• This distinction is often difficult to make
• Here, the focus is on grammatical use of
intonation
– Clearly seen in utterance-final falling tone
– Demonstrated by children age 1;6 and up
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• Proposed order of “tonal contrasts” in acquisition (Crystal, 1989):
–
–
–
–
–
–
–
–
Stage 1:
Stage 2:
Stage 3:
Stage 4:
Stage 5:
Stage 6:
Stage 7:
Stage 8:
falling tones
falling vs. level tones
falling vs. high rising tones
falling vs. high falling tones
rising vs. high rising tones
falling vs. high rising-falling tones
rising vs. falling-rising tones
Later contrasts, e.g., high vs. low rising-falling tones
• Some empirical evidence for this has been found
– Falling tones are acquired before rising tones
– Simple (unidirectional) contours are acquired before complex
(bidirectional) tones
– There is great variability among children (Snow, 1995)
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Are Falling Contours Less Marked than
Rising Contours?
• Yes
– Physiological reasons: subglottal pressure declines at the end of an
utterance
– Falling contours are acquired earlier than rising contours (Snow, 2002)
– Falling contours are less variable than rising tones (Snow & StoelGammon, 1994)
– Falling contours are substituted for rising contours (Lleó, Rakow, &
Kehoe, 2004)
– Falling contours are the most frequent contours at the 2-word stage
(Behrens & Gut, 2005)
• Perhaps not (Prieto et al., 2011)
– More recent studies using the autosegmental-metrical (AM) approach
to intonation show that young children are capable of producing more
complex melodies than falling and rising contours
– Falling contours are the predominant pattern in many of the languages
studied suggesting a bias towards recording falling tones
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Later Intonation Development
• Most studies on intonation focus on
preschoolers, but intonational development
continues into the school years
• In children age 5 through 13, production of
intonation is acquired by age 5 years but
comprehension of intonation continues to
develop through age 10 and beyond (Wells,
Peppé & Goulandris, 2004)
• This suggests that comprehension of intonation
goes hand in hand with the development of
syntactic structures
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Sidebar 7.5 Late Intonation
• Cruttenden (1974) tested children’s ability to
predict a soccer score based on the intonation
of the announcer (“Liverpool three, Everton
?”). Of 28 boys, ages 7 to 10, only one could
reliably predict whether the game ended in a
draw, win, or loss for the home team
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Cruttenden (1974)
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Atypical Prosody
• Can occur in children who are otherwise
typically developing
• Is frequently seen in children with certain
clinical diagnoses such as autism spectrum
disorder (ASD), childhood apraxia of speech
(CAS), and specific language impairment (SLI)
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Sidebar 7.6 Atypical Prosody in a
Normally Developing Child
• Some normally developing children may display unusual
prosodic patterns at certain times in development. In
Kehoe & Stoel-Gammon’s (1997) study of English-speaking
children’s multisyllabic productions, one child (28m2), aged
2;4, appeared to operate with an iambic template as shown
in the examples below:
–
–
–
–
picture
apple
banana
Helicopter
/ˈpɪktʃɚ/
/ˈæpl/͎
/bəˈnænə/
/ˈhɛləˌkɑptɚ/
[pɪkˈtʃɝ]
[æˈboʊː]
[næˈnɑː]
[kæˈtʰɝ]
7S7 English-speaking child, aged 2;4, producing multisyllabic
words (“alligator,” “elephant,” “potato,” “ avocado,” “helicopter,”
“dinosaur,” “octopus,” “telephone”) with several examples of
unusual prosodic patterns
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• Autism spectrum disorder
– McCann and Peppé’s (2003 ) review of studies between 1980 and 2002 have
reported contradictory results
– Most consistent finding: difficulty with realization and placement of
contrastive stress
– More recent studies (Chevallier, Noveck, Happé & Wilson, 2009; Peppé,
McCann, Gibbon, O’Hare, & Rutherford. 2007) show that affective and
pragmatic functions are affected more than grammatical ones
• Childhood apraxia of speech
– Mostly deficits regarding lexical and phrasal stress
7S8 Conversational speech of a boy, age 11, with a
history of severe childhood apraxia of speech
7S9 Conversational speech of the identical twin brother
of the boy in 7S9, also with a history of severe
childhood apraxia of speech
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• Specific language impairment
– Children with SLI have greater difficulty using prosodic
cues to infer grammatical rules in an artificial language,
compared to children without SLI (Weinert, 1992)
– Children with SLI tend to omit unstressed syllables more
frequently than children without SLI (Bortolini & Leonard,
2000; Owen, Dromi, & Leonard, 2001)
– Children with SLI display difficulty interpreting grammatical
and pragmatic functions in receptive prosodic tasks
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Connections
• Chapter 2: Tools for assessing prosody
• Chapter 18: More on childhood apraxia of
speech and other motor speech disorders
• Chapter 19: More on autism spectrum
disorder
• Chapter 20: Comprehensive assessment of
children’s speech abilities
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Concluding Remarks
• This chapter covers various aspects of prosody
in typically developing children as well as in
certain disorders
• Not covered in this chapter:
– Phonological aspects of prosody
– Interface of prosodic development with semantic,
pragmatic, and grammatical development
– Research investigating the acquisition of prosody
is an expanding field.
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