Infant-Directed Speech 1
Running head: INFANT-DIRECTED SPEECH AND LANGUAGE DEVELOPMENT
Exposure to Infant-Directed Speech and Its Effect on Language Development of Orphaned
and Non-Orphaned Infants
Viana S. Siniscalchi
Barnard College
Infant-Directed Speech 2
Specific Aims
A mother has just given birth to her first child. She is waiting anxiously for the
nurse to bring the tiny infant over to her bed. The nurse finally approaches and carefully
places the newborn in the mother’s arms. She opens her mouth to talk to the baby, and a
high-pitched, inflected voice escapes. Over the years, this type of speech has been labeled a
number of different ways: motherese, parentese, baby talk, infant-directed speech;
however, it has one virtually universal meaning: the speech adults- especially parentsnaturally use to address infants.
Many studies have investigated the role infant-directed speech plays in the
development of language. However, the majority of this research focuses on the speech
directed by parents to their infants. There is a visible lack of research on the type of speech
used by caregivers to address infants in orphanages and how this impacts the language
development of these orphans. This project is intended to fill this gap in the research. The
present study intends to test the hypothesis that orphaned infants receive less exposure to
infant-directed speech than non-orphaned infants; however, regardless of environment,
those infants who receive the most exposure to this type of speech when they are observed
at four-months-old will be the most linguistically advanced when tested at age one.
Today, there are an estimated 143 million orphans in the world. The findings of this
study will not only contribute to our knowledge of the importance of infant-directed speech
but also will provide insight into the types of environments orphans are exposed to and
how these environments can be modified to become more conducive for cognitive growth
and development. If this study can show that orphaned infants receive less exposure to
infant-directed speech than non-orphaned infants and that this has a visible impact on their
Infant-Directed Speech 3
language development, this issue will become more prevalent, and more extensive studies
on this topic will be pursued.
Background and Significance
Many studies have examined the use of infant-directed speech and the role it plays
in the development of language comprehension and production. In Fernald & Simon’s
(1984) study, the prosodic patterns of 24 German mothers’ speech to newborns were
analyzed. Each subject was recorded in three observational conditions: addressing her
three to five-year-old infant; addressing the absent infant as if present; and, addressing the
adult interviewer. After two-minute samples from each subject’s speech were acoustically
analyzed, it was found that in the first condition- addressing the newborn face-to-facemothers spoke with higher pitch, wider pitch excursions, longer pauses, shorter utterances,
and more prosodic repetition than in the other two conditions; in other words, “mothers
radically modified the normal tonal and temporal patterns of their speech when addressing
their newborns” (110). Interestingly, these prosodic adjustments in infant-directed speech
were demonstrated by both primaparous and multiparous mothers, thereby suggesting
that previous experience is not a prerequisite for the occurrence of this behavior. Fernald
& Simon proposed four hypotheses to explain the contributions infant-directed speech
makes to communication and language development: it gains and maintains the infant’s
attention; it communicates affect; it aids the infant in identifying the mother; it helps
develop speech perception skills.
In Fernald et al.’s (1989) study, the prosodic modifications in both mothers’ and
fathers’ infant-directed speech were compared in French, Italian, German, Japanese, British
English, and American English. In each of the language groups, five mothers and five
Infant-Directed Speech 4
fathers were recorded while speaking to their infant and to an adult in the home
environment. Speech samples were analyzed, and results showed that across languages,
both mothers and fathers used higher mean fundamental frequency, shorter utterances,
and longer pauses in infant-directed than adult-directed speech. Furthermore, American
English parents demonstrated the most prosodic modifications, specifically in the extent of
intonational exaggeration. The results of this study demonstrate that in many ways the
prosodic elements of infant-directed speech are universal; however, there are still
language-specific variations of this type of speech.
In Fernald’s (1985) study, the hypothesis that infants would choose to listen more
often to infant-directed speech than adult-directed speech was tested. Tape recordings
were made of ten women- none of whom was the mother of an infant who participated in
the study- in two conditions: talking to their four-month-old infants; talking to the adult
interviewer. The results showed that 33 of the 48 four-month-old infants tested turned
their heads more often toward the recordings of infant-directed speech than those of adultdirected speech, thus demonstrating that these infants preferred to listen more often to
infant-directed speech. Furthermore, since the speech samples were extracted from
women who were unfamiliar to the infant subjects, the results showed that infants
demonstrate a preference for infant-directed speech than for their own mother’s voice.
Fernald proposed that the simplified lexicon, exaggerated intonation, and pitch contours of
infant-directed speech make it acoustically attractive to infants.
Werker & McLeod (1989) also examined infants’ preference for infant-directed
speech delivered by both females and males. In the first experiment, infants aged 18 to 30
weeks were shown video recordings of male and female adults reading identical scripts in
Infant-Directed Speech 5
both infant-directed and adult-directed speech. In the second experiment, the same design
was used with approximately four to nine-month-olds. The results of both experiments
showed that these infants exhibited significantly greater attentiveness to male and female
infant-directed than adult-directed speech. Furthermore, by using video recordings
instead of audio recordings, Werker & McLeod were able to demonstrate that facial as well
as vocal features of infant-directed speech play an important role in infants’ preference for
infant-directed over adult-directed speech.
These four studies have demonstrated that both mothers and fathers use infantdirected speech when addressing their infant, regardless of whether or not it is their first
child. Furthermore, it has been shown that many prosodic elements of infant-directed
speech are universal. Finally, studies have demonstrated that infants at approximately four
months of age prefer to listen to infant-directed speech than adult-directed speech.
However, does this type of speech serve any benefits to the development of language
comprehension and production?
In Fernald’s (1989) article, a number of books and studies examining the effect of
infant-directed speech on language development are referenced. M.M. Lewis’s Infant
Speech (1936/1951) “attributed a central role to intonation in the development of both
comprehension and production in the first two years” (1497). Since infants use
exaggerated intonation to express their own desires and intentions, Lewis proposed that
prosodic information in infant-directed speech initially plays a more noticeable role than
phonetic information in language perception and development. Fernald also referenced
studies by Garnica (1977) and Sachs (1977) in which it was demonstrated that exaggerated
intonation functions to “engage the infant’s attention and maintain social interaction”
Infant-Directed Speech 6
(1498). Studies by Lewis (1936), Papousek & Papousek (1981), and Stern (1985) showed
that intonation also functions to communicate affect to preverbal infants. Finally, Fernald
mentioned a study by Nooteboom & Kruyt (1987) in which it was found that intonation
encodes information about the “syntactic and discourse structure of language” (1498); in
other words, intonation helps to teach grammar to infants. Kuhl et al.’s (1997) study also
demonstrated the important role that infant-directed speech plays in teaching infants
about linguistics. The results of this study showed that in the United States, Russia, and
Sweden, parents addressing their infants produced vowel spaces that were acoustically
more stretched. Kuhl et al. suggested that the phonetic modifications of infant-directed
speech help to teach infants the sound system of their native language in two ways: by
separating sounds into contrasting categories and by highlighting the parameters on which
speech categories are distinguished.
In her own study, Fernald (1989) examined the ability of intonation to relate
meaningful information about the communicative intent of the speaker in speech
addressed to pre-verbal infants and adults. Samples of infant-directed and adult-directed
speech were recorded from five mothers in five categories: attention-bid, approval,
prohibition, comfort, and game/telephone. 80 adults subjects listened to the speech
samples and were told to identify the communicative intent of the speakers by categorizing
the samples into the five groups listed above. It was found that subjects were able to
identify the communicative intent of the speaker with significantly higher accuracy in
infant-directed than adult-directed speech. The results of this study demonstrated that
intonation conveys important information to infants; the prosodic elements of infant-
Infant-Directed Speech 7
directed speech are more distinctive and valuable than those of adult-directed speech, and
therefore, help to provide cues to the speaker’s intent.
Characterized by “higher mean pitch, wider pitch range, longer pauses, shorter
phrases, and more prosodic repetition,” infant-directed speech is used by both mothers and
fathers when addressing their pre-verbal infants (Fernald & Simon, 1984). Numerous
studies have demonstrated that infants display a preference for infant-directed as opposed
to adult-directed speech and that infant-directed speech conveys important information
about the affect and intent of the speaker. Furthermore, infants learn about the phonetic
and syntactic building blocks of language by listening to the exaggerated intonation of
infant-directed speech. Therefore, it is evident that exposure to infant-directed speech as a
pre-verbal infant plays an essential role in language development, comprehension, and
production.
The majority of research on infant-directed speech and its effect on language
development uses non-orphaned infants as subjects; often, in these studies, the infantdirected speech of mothers and fathers is recorded and played to infants to elicit a
response, or the actual communication between a parent and his or her child is observed.
However, it is very difficult to find any research which examines orphans’ exposure to
infant-directed speech. This project will attempt to answer the following questions: Do
caregivers in orphanages address orphaned infants with infant-directed speech, and how
often do they use this type of speech? Are non-orphaned infants exposed to more infantdirected speech than orphaned infants? How does the level of language development of
orphaned infants at age one differ from that of non-orphaned infants at age one, and how
does this difference relate to their amount of exposure to infant-directed speech?
Infant-Directed Speech 8
Research Design and Methods
Orphanage Condition
Participants will consist of 50 infants- male and female- aged four months living in
American orphanages. More than one orphanage may be used to reach the desired number
of participants for the study. We will need the consent and cooperation of the orphanages
we choose to use in our study; the consent form will clearly outline the procedure so the
orphanages are completely aware of the level of involvement required by the staff and
infants chosen to participate. All participants must have had normal births and must not
have any documented health problems; preterm infants and infants born to mothers who
smoked, consumed alcohol, and/or engaged in drug use during pregnancy will be excluded
from this study. Only infants whose caregivers speak English to them may participate in
the study. These conditions are necessary to control for other factors that could affect the
results of this study.
Data collection will take place over three consecutive days and will last each day
from 9 am to 1 pm. To make sure the caregivers do not alter their speech behavior when
interacting with the infants participating in the study, the experimenters will say that a
study on infant social behavior is being conducted. When the study concludes after three
days, we will debrief the caregivers and tell them we are studying orphans’ exposure to
infant-directed speech and its effect on language development. We will set up an audio
recorder and a video camera in the room or nursery where each infant participant spends
most of his or her time. If the infant participants are kept in separate rooms in the
orphanage, then each room will get its own audio recorder and video camera; if all the
infants share a communal nursery in the orphanage, then one video camera will be set up
Infant-Directed Speech 9
in the room and each participant’s crib will receive its own audio recorder. These devices
will record the communication between caregiver and infant for four hours a day for three
days.
When the infant participants reach age one, we will track them down and
administer to them the Preschool Language Scale, Fourth Edition (PLS-4), which measures
receptive and expressive language of children aged zero to six years. The supplementary
Caregiver Questionnaire will also be administered so that the caregiver(s) can share their
knowledge of the infant’s typical communication.
Home Condition
Participants will consist of 50 infants- male and female- aged four months living in
American households. We will need the consent and cooperation of the parents whose
infants will participate in the study; the consent form will clearly outline the procedure so
the parents are completely aware of the level of involvement required by them and their
infants. All participants must have had normal births and must not have any documented
health problems; preterm infants and infants born to mothers who smoked, consumed
alcohol, and/or engaged in drug use during pregnancy will be excluded from this study.
The infants that participate in the study must be singletons. English must be the primary
language spoken in the home. These conditions are necessary to control for other factors
that could affect the results of this study. Since previous studies like Fernald et al. (1989)
have demonstrated that both mothers and fathers use infant-directed speech to address
their infants, the parent who is observed interacting with the infant participant may be
male or female.
Infant-Directed Speech 10
Data collection will take place over three consecutive days and will last each day
from 9 am to 1 pm. To make sure the parents do not alter their speech behavior when
interacting with the infants participating in the study, the experimenters will say that a
study on infant social behavior is being conducted. When the study concludes after three
days, we will debrief the parents and tell them we are studying infants’ exposure to infantdirected speech and its effect on language development. We will set up an audio recorder
and a video camera in the room or nursery where the infant participant spends most of his
or her time. These devices will record the communication between parent and infant for
four hours a day for three days.
When the infant participants reach age one, we will track them down and
administer to them the Preschool Language Scale, Fourth Edition (PLS-4). The
supplementary Caregiver Questionnaire will also be administered so that the parent(s) can
share his or her knowledge of the infant’s typical communication at home.
Data Analysis
The audio data will be processed using a pitch-extraction computer program
modeled after the program used in Fernald & Simon’s (1984) study; this program will
provide measurements of the frequency, amplitude, and duration of speech samples. We
will use Fernald & Simon’s (1984) definition of infant-directed speech- higher mean pitch,
wider pitch range, longer pauses, shorter phrases, prosodic repetition- to determine
whether or not the speech samples acquired in this study qualify as infant-directed speech.
We will also analyze the amount of time orphanage caregivers and parents spend
addressing the infants with infant-directed speech. The infants’ scores from the PLS-4 and
information obtained from the Caregiver Questionnaire will be integrated to create
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aggregate scores. We will use an independent two-sample t-test to analyze and compare
the data of the two groups.
Predicted Results
It is hypothesized that orphaned infants receive less exposure to infant-directed
speech than non-orphaned infants; however, regardless of environment, those infants who
receive the most exposure to this type of speech when they are observed at four-monthsold will be the most linguistically advanced when tested at age one.
There are some limitations of the proposed procedure of this study. First of all,
there is the possibility that some orphaned infants participating in the study may have
more than one caregiver, so they may be constantly exposed to infant-directed speech from
one caregiver and rarely exposed to this speech from another caregiver, and this
discrepancy will be observed and recorded. On the other hand, non-orphaned infants will
most likely receive a steady amount of exposure to infant-directed speech. Another
limitation is biological connectivity; relatives may be more likely to engage in infantdirected speech with infants than non-relatives. Gender of the infants can also affect the
results; it is possible that one gender linguistically develops more quickly than the other.
Another limitation of this study is the small sample size. This project is meant to be an
introductory study. We want to focus on American infants not only because, according to
Fernald et al. (1989), American parents show the most extreme prosodic modifications
when communicating with infants but also because it is the most culturally and socially
relevant and generalizable. However, since the United States does not have as large a
population of orphaned infants as other nations, especially in Europe, Asia, and Africa, the
subject pool of this study is limited. However, if the results of this study support our
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hypothesis and suggest that the orphanage environment could be modified to become
more conducive for language development, it is a strong possibility that more funding
would be issued to more extensive studies on this topic, which could extend their research
to other nations where the orphan population, especially of infants, is much greater.
Infant-Directed Speech 13
References
Fernald, A. (1985). Four-month-old infants prefer to listen to motherese. Infant Behavior
and Development, 8, 181-195.
Fernald, A. (1989, December). Intonation and communicative intent in mothers' speech to
infants: Is the melody the message? Child Development, 60(6).
Fernald, A., & Simon, T. (1984). Expanded intonation contours in mothers' speech to
newborns. Developmental Psychology, 20(1), 104-113.
Fernald, A., Taeschner, T., Dunn, J., Papousek, M., de Boysson-Bardies, B., & Fukui, I. (1989).
A cross-language study of prosodic modifications in mothers' and fathers' speech to
preverbal infants. Journal of Child Language, 16(3), 477-501.
Kuhl, P. K. (1997, August). Cross-language analysis of phonetic units in language addressed
to infants. Science, 277(684), 684-686.
Werker, J. F., & McLeod, P. J. (1989). Infant preference for both male and female infant
directed talk: A developmental study of attentional and affective responsiveness.
Canadian Journal of Psychology, 43(2), 230-246.