Better baby communication:
Why your baby prefers infant-directed speech
© 2008 - 2017 Gwen Dewar, Ph.D., all rights reserved
Baby communication operates on multiple sensory channels, including sight and touch.
But of course human beings are linguistic creatures, so we expect our infants to learn language. How does this happen?
You might argue that our babies deserve all the credit.
- They listen to a sea of confused sound, and figure out that certain segments of sounds are words.
- They teach themselves to reproduce the speech sounds they hear -- by listening, babbling, making corrections, and babbling again.
They infer the meanings of words by interacting with conversation partners and observing contingencies. If I say "wa-wa," she hands me my drinking cup. Hmmm.
However you look at it, it's an amazing feat. Without textbooks or dictionaries or explicit instruction, babies acquire language.
But that doesn't mean that babies work everything out on their own, without any help. If you've ever struggled to understand a new language, you know that not every speaker is equally easy to understand. Some folks, noticing your difficulties, alter their normal speech patterns to make their meanings more obvious. Does the same thing happen for infants?
Enter Exhibit A, the phenomenon that researchers call "infant-directed speech."
Also called "parentese," or "motherese," it's a form of communication that people seem to adopt naturally when they interact with a baby.
Suddenly their vocal pitch goes up. They speak more musically, using a wider pitch range (i.e., more distance between the highest- and lowest-pitched sounds). They change the tonal color, or timbre, of their voices (Piazza et al 2017), and exaggerate their emotional tone (Kemler-Nelson et al 1989; Saint-Georges et al 2003).
They speak more slowly, and use shorter, simpler sentence structure. They tend to repeat themselves a lot, and give certain words emphasis by uttering them in isolation. Instead of saying, "look at the teddy bear," they might call out, "bear!" (Christia and Siedl 2013; Fernald 2000).
They may also exaggerate the articulation of certain vowel sounds and position target words at the end of a sentence. Look at the BALL! (Swanson and Leonard 1994).
Not everyone does it, but it's remarkably common. Mothers do it. Fathers do it. Children do it. People lacking experience with babies do it (Broesch and Bryant 2017; Fernald et al 1989; Jacobson et al 1983).
And this distinctive style of baby communication has been documented in a wide range of languages, including languages indigenous to
- Africa and the Middle East (Arabic and Xhosa, a Bantu click language),
- The Americas (Comanche)
- Australia (Warlpiri)
- East Asia (Cantonese, Mandarin, Korean, Japanese, and Gilyak, a Siberian language)
- South Asia (Bengali, Hindi, Marathi, and Sinhala, a Sri Lankan language)
- Europe (English, French, German, Italian, Latvian, and Swedish)
references, see (Das 1989; Dil 1971, Ferguson 1964; Fernald et al 1989;
Fernald and O’Neill 1993; Kelkar 1965; Meegaskumbura 1980; Saint-Georges et al 2013; Sulpizio et al 2017)
So is this "baby talk" a human universal?
It depends on how you define "universal." As we've alread noted, infant-directed speech isn't practiced absolutely everywhere by everyone. Parents who are
depressed or self-conscious aren't so good at ID speech (e.g., Kaplan et
al 2007). And some parents may be discouraged by cultural attitudes.
instance, anthropologists have reported that the Kaluli of New Guinea
don't engage their babies in conversation (Sheiffelin and Ochs 1996).
It's also been reported that the Quiché Mayan speak to their babies in
the same pitch that they use to address adults (Ratner and Pye 1984).
these cases are exceptions to the rule. Yes, infant-directed speech is
subject to individual differences and cultural influences. But you can
say the same thing about most human behavior—including other parenting
practices, like breastfeeding.
So some researchers are
comfortable characterizing infant-directed speech as a human universal.
Indeed, researchers like Anne Fernald and Mary Monnot have argued that
baby talk is an evolved, species-specific adaptation (Fernald 1992;
According to this idea, infant-directed speech
evolved to facilitate baby communication. It's a tutorial style of
speech, one designed to help babies develop social skills, forge stronger
emotional attachments, and learn language.
It's an intriguing view, especially if you consider these findings.
1. Babies -- even newborn babies -- prefer communication partners who use infant-directed speech
In a classic experiment, researchers Robin Cooper and Richard Aslin presented 2-day old infants with audio recordings of adult speech.
The babies could control how long each playback lasted by turning their heads toward a loudspeaker.
In some trials, babies heard infant-directed speech. In other trials, they heard adult-directed speech.
Cooper and Aslin found that the newborns turned their heads longer in response to infant-directed speech (Cooper and Aslin 1990).
Similar experiments have been performed on older babies, with the same results. In one study, five-month-old babies showed a preference for strangers who addressed them with infant-directed speech, even after the talking had ended (Schachner and Hannon 2011). But the behavior of newborns seems especially compelling. It suggests that babies are born with an unlearned preference for infant-directed speech.
2. Infant-directed speech is an attention-grabber
Experimental research has shown that babies' brains pay more attention to infant-directed speech.
In one study of 3-month old infants, researchers played back recordings of adult voices to sleeping babies. In some trials, babies heard infant-directed speech. In other trials, they heard adult-directed speech. When sleeping babies listened to the baby talk, they experienced an increased blood flow to the frontal area of their brains (Saito et al 2006).
Similarly, cognitive neuroscientists have
measured event-related potentials, or ERPs, in 6- and 13-month old
babies as they listened to both infant-directed and adult-directed
speech. The babies’ brains experienced more electrical activity when
they listened to baby talk (Zaigl and Mills 2007).
Why does baby talk grab the attention?
It might be the higher pitch.
Experiments have shown that infants listen longer to songs when they are sung in a higher pitch (Trainor and Zacharias 1998). There is also evidence that human mothers raise voice pitch when they want to get the attention of a seemingly bored infant (Niwano and Sugai 2003).
And high-pitched vocalizations are used as attention-getters among a
variety of species. For example, macaque monkeys use high-pitched calls to get
the attention of other group members (Koda and Masataka 2003).
But why should human infants show such this preference? It could be that it's easier for them to pick out high-pitched voices against background noise. Alternatively, babies might perceive high-pitched voices as less aggressive (Kalashnikova et al 2017).
And it might be a byproduct of the infant's interest in his or her own voice. According to this idea, infants are motivated to attend to their own voices because they need to fine-tune the speech sounds they make. As a result, they possess a bias for voices with infant-like characteristics (Massapollo et al 2016).
Infant-directed speech might command attention for other reasons, too, such as the greater range of pitch, and more exaggerated emotional tone.
This seems possible because
- babies like it when men use infant-directed speech, even though male
voices don’t reach the same heights of pitch than women’s voices do
(Werker and McLeod 1989),
babies like to listen to adult-directed speech when it is highly-charged with pleasant emotion (Singh et al 2002), and
- when adult-directed speech is highly emotional, it takes on many of the
characteristics of baby communication. This includes a higher pitch,
but it also includes a greater pitch range and slower tempo (Trainor et
3. Infant-directed speech makes emotions -- and intentions -- more obvious
Cultures vary widely in the amount of emotion that is conveyed in speech. But within a given culture, infant-directed speech is more demonstrative and emotional.
Does this make the intentions of a baby talker more obvious?
It seems likely. After all, some Americans speak to their pets in a sing-song, emotionally-exaggerated way (Mitchell 2001; Burnam et al 2002). Your dog might not understand the words, but he does understand the tone.
So we shouldn’t be surprised if members of our own species have an easier time interpreting the emotions of infant-directed speech.
In an interesting cross-cultural experiment, researchers played back recordings of American English-speaking mothers to adults of the Shuar, an indigenous South American group that practices hunting and horticulture (Bryant and Barrett 2007).
The Shuar adults could reliably identify which utterances were baby talk. And, despite no knowledge of English, adult listeners were able to classify the speakers’ intentions into four categories--prohibition, approval, comfort, or attention.
They could do this when the English-speaking utterances were adult-directed.
But they performed even better when the utterances were baby talk.
Do babies pick up on the emotional cues of infant-directed speech?
Experiments suggests that they can.
one study, Stanford University researcher Anne Fernald and colleagues
presented 5-month old American babies with speech they had never heard
before: Vocalizations of approval and prohibition spoken in German,
Italian, and Japanese.
Then researchers noted the babies’ affective responses to each vocalization.
team found that the American babies listened with neutral affect to the
Japanese utterances—perhaps because Japanese moms don’t use as wide a
pitch range in their infant-directed speech (Fernald et al 1989).
when it came to the German and Italian utterances, the babies responded
with the appropriate emotion to each one-—positively to approvals and
negatively to prohibitions.
However, this was true only
when the babies had been presented with infant-directed speech. When
the messages of approval or prohibition took the form of adult-directed
speech, infants did not distinguish between them.
similar experiment was performed on Canadian babies listening to
utterances in a non-native language. In this case, 4- to 9-month old
babies watched a videotape of a woman speaking Cantonese. When the
woman's intention was baby communication, infants were more likely to
respond with pleasant emotions (Werker et al 1994).
4. There is evidence that infant-directed speech helps babies learn language
We've seen how infant-directed speech might help babies pay closer
attention. It might also help babies "read" the emotions and intentions
But what about learning to speak?
Experiments suggest that infant-directed speech can help infants develop several key speech perception skills, including
- the ability to discriminate between different speech sounds
- the ability to detect the boundaries between words in a stream of speech
- the ability to recognize distinct clauses in a stream of speech
- the ability to "read lips," or match visual cues to their corresponding speech sounds
And infant-directed speech may help adults, too.
experiments conducted by Roberta Golinkoff and Anthony Alioto,
English-speaking adults found it easier to learn new Chinese words when
the words were spoken in the baby talk register (Golinkoff and Alioto
Does this imply that infant-directed speech is a kind of "tutorial" mode of baby communication? It seems to. In fact, there is
even evidence suggesting that babies learn speech faster when their
parents use particularly expressive forms of infant-directed speech.
For example, in families where parents use infant-directed speech, babies who spend more time in one-on-one conversion develop better language skills (Ramírez-Esparza et al 2017).
For more details, see this article about
language learning, baby communication, and infant-directed speech.
Other channels of baby communication
Speech isn't the only way that parents can talk with babies. As deaf parents know, babies are also receptive to learning sign language. Even babies of hearing parents may benefit from using gestures during speech. For more information, see this article on the science of baby signs.
Furthermore, it isn't merely exposure to words or hand signs that help babies learn. Studies suggest that eye contact plays a crucial role. Read more here.
References: Better baby communication
Broesch T and Bryant GA. 2017. Fathers' Infant-Directed
Speech in a Small-Scale Society. Child Dev. 2017 Feb 27. doi:
10.1111/cdev.12768. [Epub ahead of print]
Bryant GA and Barrett HC. 2007. Recognizing intentions in infant-directed speech Psychol Sci. 18(8):746-51.
D, Kitamura C, and Vollmer-Conna U. 2002. What's new, pussycat? On
talking to babies and animals. Science 296(5572):1435.
Cristia A and Seidl A. 2013. The hyperarticulation hypothesis of infant-directed speech. J Child Lang. 13:1-22.
RP and Aslin RN. 1994. Developmental differences in infant attention to
the spectral properties of infant-directed speech. Child Dev.
Das, V. 1989. Voices of children. Daedalus 118: 263-294.
Dil A. 1971. Bengali baby talk. Word 27:11-27.
L and Jacob V. 2006. Prosodic and lexical aspects of maternal
linguistic input to late-talking toddlers. Int J Lang Commun Disord.
Golinkoff RM and Alioto A. 1995. Infant-directed
speech facilitates lexical learning in adults hearing Chinese:
implications for language acquisition. J Child Lang. 22(3):703-26.
Ferguson CA. 1964. Baby talk in six languages. American Anthropologist 66: 103-114.
Fernald A. 2000. Speech to infants as hyperspeech: Knowledge-driven processes in early word recognition. Phonetic 57: 242-254.
A. 1992. Human maternal vocalizations to infants as biologically
relevant signals: An evolutionary perspective. In: JH Barkow, L Cosmides
and J Tooby (eds), The Adapted Mind: Evolutionary psychology and the
generation of culture (pp. 391-428). New York: Oxford University Press
A, McRoberts GW, and Swingley D. 2001. Infants' developing competence
in recognizing and understanding words in fluent speech. In J.
Weissenborn and B. Hohle (eds.) Approaches to bootstrapping:
Phonological, lexical, syntactic and neurophysiological aspects of early
language acquisition, Vol. I. Amsterdam: John Benjamins.
A., & O'Neill, D. K. (1993). Peekaboo across cultures: how mothers
and infants play with voices, faces, and expectations. In K. MacDonald
& D. Pelligrini (Eds.), Parent-child play: Descriptions and
Implications, (p. 259 - 286). New York: SUNY.
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. J Child Lang. 1989.16(3):477-501.
J and Nelson K. 1993. The relation of maternal language to variation in
rate and style of language acquisition. J Child Lang. 20(2):313-42.
JL, Boersma DC, Fields RB and Olson KL. 1983 Paralinguistic Features of
Adult Speech to Infants and Small Children. Child development 54:
Kalashnikova M, Carignan C, Burnham D. 2017. The origins of
babytalk: smiling, teaching or social convergence? R Soc Open Sci. 4(8):170306.
Kaplan PS, Sliter JK, and Burgess AP.
2007.Infant-directed speech produced by fathers with symptoms of
depression: effects on infant associative learning in a
conditioned-attention paradigm. Infant Behav Dev. 30(4):535-45.
Kelkar A. 1965. Marathi baby talk. Word 20: 40-54.
H and Masataka N. 2002. A pattern of common acoustic modification by
human mothers to gain attention of a child and by macaques of others in
their group. Psychol Rep. 91(2):421-2.
Hirsh-Pasek K, Jusczyk PW, Cassidy KW. 1989. How the prosodic cues in
motherese might assist language learning. J Child Lang. 16(1):55-68.
Laughren M. 1984. Warlpiri baby talk. Australian Journal of Linguistics 4(1): 73-88.
Masapollo M, Polka L, Ménard L. 2016. When infants talk,
infants listen: pre-babbling infants prefer listening to speech with infant
vocal properties. Dev Sci. 19(2):318-28.
Meegaskumbura PB. 1980. Tondol: Sinhala baby talk. Word, 31(3), 287-309.
R.W. 2001. Americans' talk to dogs: Similarities and differences with
talk to infants. Research on Language and Social Interaction, 34(2),
Monnot M. 1998. Function of infant-directed speech. Human Nature 10(4): 1045-6767.
K and Sugai K. 2003. Maternal accommodation in infant-directed speech
during mother's and twin-infants' vocal interactions. Psychol Rep.
Piazza EA, Iordan MC, Lew-Williams C. 2017. Mothers
Consistently Alter Their Unique Vocal Fingerprints When Communicating with
Infants. Curr Biol. 27(20):3162-3167.e3.
Ratner NB and Pye C. 1984. Higher pitch in BT is not universal: acoustic evidence from Quiche Mayan. J Child Lang. 11(3):515-22.
Ramírez-Esparza N, García-Sierra A, Kuhl PK. 2017. Look
Who's Talking NOW! Parentese Speech, Social Context, and Language Development
Across Time. Front Psychol. 8:1008.
Saint-Georges C, Chetouani M, Cassel R, Apicella F, Mahdhaoui A, Muratori F, Laznik MC, Cohen D. 2013. Motherese in interaction: at the cross-road of emotion and cognition? (A systematic review). PLoS One. 8(10):e78103.
Y, Aoyama S, Kondo T, Fukumoto R, Konishi N, Nakamura K, Kobayashi M,
and Toshima T. 2007. Frontal cerebral blood flow change associated with
infant-directed speech. Arch Dis Child Fetal Neonatal Ed. 92(2):F113-6.
Schachner A and Hannon EE. 2011. Infant-directed speech drives social preferences in 5-month-old infants. Dev Psychol. 47(1):19-25.
B and Ochs E. 1996. The microgenesis of competence: Methodology of
language socialization. In D.I. Slobin, J. Gerhardt, A. Kyratziz, and J.
Guo (eds.): Social interaction, social context and language: Essays in
honor of Susan Ervin-Tripp. Lawrence Erlbaum Associates, pp.251-264.
Sulpizio S, Kuroda K, Dalsasso M, Asakawa T, Bornstein MH,
Doi H, Esposito G, Shinohara K. 2017. Discriminating between mothers' infant-
and adult-directed speech: Cross-linguistic generalizability from Japanese to
Italian and German. Neurosci Res. pii: S0168-0102(17)30166-9.
Swanson LA and Leonard LB. 1994. Duration of function-word vowels in mothers' speech to young children. J Speech Hear Res 37: 1394-1405.
Thiessen ED, Hill EA and Saffran JR. 2005. Infant-directed speech facilitates word segmentation. Infancy 1(1): 53-71.
LJ, Austin CM, Desjardins RN. 2000. Is infant-directed speech prosody a
result of the vocal expression of emotion? Psychol Sci. 11(3):188-95.
JF, Pegg JE, and McLeod PJ. 1994. A cross-language investigation of
infant preference for infant-directed communication. Infant behavior and
development. 17: 323-333.
Zangl and Mills. 2007. Increased Brain Activity to Infant-Directed Speech in 6- and 13-Month-Old Infants. Infancy 11: 1 – 62.
Photo credits for "Baby Communication":
title image of mother and infant by Pascal Maramis /flickr
image of woman smiling down on baby by Tim Samoff / flickr no derivatives
image of father and baby ©iStockphoto.com/daniel rodriguez
image of newborn clutching mother by Nick Koch Weiler / flickr
Content of "Baby Communication" last modified 12/17