Chapter 4
An Acoustic Phonetic Catalog of
Prespeech Vocalizations from a
Developmental Perspective
Eugene H. Buder
Anne S. Warlaumont
D. Kimbrough Oller
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Introduction
• Protophones (volitional prespeech vocalizations)
can be considered precursors to speech
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Only humans produce them
Developmental sequence
Increasingly resemble speech
Disruptions are seen in children with disorders
• This chapter
– Presents a glossary of protophones with details on how to
code them
– Comments on order of occurrence
– Presents spectrograms and sound files with notes on
audible and acoustic features
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History of the Protophone Approach to
Studying Infant Vocalizations
• “Discontinuity theory” (Jakobson, 1941 in
German, 1968 in English translation): Babble is
random and unrelated to speech development
later on
• Evidence to the contrary: Babble is closely related
to early speech development (Stoel-Gammon &
Cooper, 1984)
– The characteristics of sounds in the late babble stages
resemble the segments and syllable structures of first
words
– For a while (approximately ages 11 to 20 months),
infants produce both babble and words
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History of the Protophone Approach, cont.
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Prior to the late 1970’s, pre-speech vocalizations were either
– Transcribed phonetically using the same phonetic categories as those used for adults, or
– Focused on acoustic features using the same parameters as those used for adults
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New approach: “Protophones” (Koopmans-van Beinum & van der Stelt, 1986;
Oller, 1980, Stark, 1980)
Protophones are
– More primitive productions that are different from the sounds catalogued in the International
Phonetic Alphabet
– Precursors of speech sound development
– Reflexive, non-volitional sounds such as cries, laughs, and burps, are not protophones
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The stages of protophone development appear to be independent of the child’s
ambient language
Research on protophones
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Hearing impairment, autism (Paul et al., 2011; Sheinkopf et al., 2000)
Infant/caregiver dyads (Warlaumont et al., 2010; Buder et al., 2010)
Social reinforcement (Goldstein & Schwade, 2008)
Automatic classification (Warlaumont et al., 2010)
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Guidelines for Coding Protophone
Categories
• Exclude fixed signals (e.g., crying, laughter) and sounds of
physiologic origin (e.g., sneezing)
• Code at the utterance level
– Breath groups can be used to determine utterance boundaries
• Forced-choice protocol may be used for certain features
– E.g., use the most salient feature for phonation qualities for squeal vs.
growl, even if the utterance has elements of two or more
– Allow combinations of phonatory and articulatory features, e.g., a
canonical babble can also be a squeal
• Focus on general categories (often overlooking narrow ‘phonetic’
details)
– Take guidance from caregivers, who regularly interpret and group
infant’s vocalization as possible signals to be acted on
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Glossary of Protophone Categories
• Reflexive
– Cries, fusses
– Laughs
– Vegetative sounds
• Protophone
– Phonation related
– Syllabification/articulation related
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Phonation Related Protophones
• Quasivowel (vocant: articulatory tract in neutral
position)
• Full vowel (vocant: adjusted articulatory tract)
• Squeal: high pitch
• Growl: harsh vocal quality or low pitch (often fry)
• Whisper: no phonation
• Yell: loud
• Ingressive vocalization
• Ingressive-egressive sequence
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Articulation and Syllabification Related
Protophones
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Raspberry: trill or vibrant
Click: release of negative pressure
Goo: closure usually back of tract, erratic timing
Glottal sequence: vocants with glottal stop
interrupts
• Marginal babble: closant plus vocant but
imprecise timing
• Canonical babble: syllabic timing
– Reduplicated: repetition of an identical syllable [dada]
– Variegated: string of non-identical syllables [mani]
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Comments on Order of Development
and Ages of Onset in Protophones
• Numerous publications have addressed stages of protophone
development
• Similar findings across studies (Oller, 2000)
– Crying and vegetative sounds are present at birth but laughter
emerges around age 4 months
– The earliest protophones including quasivowels and glottal stop
sequences occur right after birth
– Gooing occurs at 1 to 4 months, usually in interaction with caregivers
– By 3 months, many new protophones appear (full vowels, raspberries,
squeals, growls, yells, whispers, marginal babble)
– Canonical babbles appear in the second half of the first year
• Whether reduplicated babble always precedes variegated babble is not clear
– Onset of canonical babble past age 10 months is grounds for clinical
concern; seen in children with profound hearing impairment, often in
Down syndrome, and Williams syndrome
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An Acoustic Phonetic Catalog of
Examples of Selected Protophones
4S1 through 4S20: Protophone Examples 1 through 20
Note: These samples were selected to provide guidance with subtle
characteristics of protophones. Excluded are non-protophones and
protophones with obvious perceptual and acoustic characteristics
(whispers, clicks, extensive examples of canonical babble) and
those categories with less clearly defined characteristics (variegated
babble, gibberish)
Editors also provided 4S21: Cry of a one-week-old infant, and
4S22: Recording of a 9-week-old infant, to support Suggested
Activities
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F1
Example 1. A quasivowel, produced by an infant aged 3 ½ months.
Quasivowels are produced with a neutral (resting) vocal tract
configuration and are typically quiet and short.
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Example 2. Another quasivowel, produced by the same infant at the
same age (3½ months) as Example 1.
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Example 3. A goo, preceded by a quasivowel, and followed by a full vowel, produced by
the same infant at the same age as preceding examples.
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We categorized Example 4 on the left as a quasivowel, and Example 5 on the right as a
full vowel. These examples are displayed here side by side to reinforce some additional
principles and distinguishing characteristics regarding quasivowels and full vowels as
isolated types of vocalizations (i.e., as nucleus-only vocalizations lacking syllabic
margins). While Example 5 has been coded as a full vowel, rather than a quasivowel, it
is not the most unambiguous of cases. Examples 4 and 5 were produced by a much
older infant, aged approximately 11 months, which reinforces the fact that earlyemerging protophones may still occur even though infants this age will normally also be
producing fully articulated canonical syllables.
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Example 6 returns to the younger infant from previous examples (aged 3½ months), and
illustrates a more complex sequence that includes some previous types, including goo and
full vowel, and introduces a new protophone type, the raspberry.
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Examples 7 and 8 are presented here side by side to compare varieties of raspberry. The
raspberries presented in examples 6-8 were produced by the same 3 ½ month old child during
one 20 minute recording session. One possible interpretation of this phenomenon is that the
infant was exploring her ability to produce sounds by controlling pressures and airflows with a
valving mechanism other than at the glottis (i.e., the lips). Depending on the speed of labial
vibration a raspberry may be a trill, a vibrant with salient roughness (as in Example 6), or even
a very high frequency vibrant that produces a tonal characteristic, like the lip action using in
playing a trumpet.
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Example 9 introduces a glottal sequence. This vocalization is one of many produced in a single
20 minute session by an infant nearly 4 months of age, who seemed to be practicing with the
glottal valving operation. Because the beginning of the utterance includes a presumably velar
closure, the utterance would best be characterized within the forced choice system as a goo (the
most advanced protophone category to which the utterance pertains), but here we illustrate
that it also has the characteristics of a glottal stop sequence.
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Example 10 is a growl, produced by a different
child but also at about 4 months of age.
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Examples 11 and 12 above are two more examples of growls and help illustrate that the term
encompasses quite a range of possible variations from normal phonation. The growl on the
left was produced by an older infant at about 10 months of age, and the growl on the right
by a different infant at about 4 months of age.
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Example 13 is a squeal, produced by the same 4-monther who produced the growl of
Example 12 (and recorded in the same session). Vertical lines on the bottom plot are at 1
kHz intervals.
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Example 14 is another squeal, produced by the
same infant in Example 13, but at 6 months.
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Example 15 is a yell, produced by a 10 month old infant.
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Examples 16 on the left is a marginal babble produced by a 12 month old girl, and Example
17 on the right is a canonical babble produced by the same infant in the same recording
session.
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Example 18 on the left is another marginal babble produced by a 10
month old girl, and Example 19 on the right is a canonical babble
produced by the same child in the same recording session.
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Example 20 is a single breath group sequence of reduplicated canonical syllables, a kind of
celebration of babbling that adult listeners recognize as truly speech-like and to which they are
usually therefore tempted to ascribe meaning. The infant producing this example was 10 ½
months old.
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Connections
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Chapter 3: biological substrates
The current chapter: pre-speech vocalizations
Chapter 5: from pre-speech to first words
Chapter 19: pre-speech development in
infants with hearing impairment and
developmental disabilities
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Concluding Remarks
• This chapter discusses the categorization of prespeech vocalizations into protophones
– Historical perspectives
– Theoretical perspectives
– Practical guidelines on how to apply protophone
categorization
– Protophone development
– Increasing similarities to speech
• Timing
• Articulation
• Complexity
– Audible and Spectrographic features
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