By Stephen Beech via SWNS
Babies squeal and growl in distinct “clustering” patterns throughout the first year of life, reveals new research.
The early vocal attempts are key to speech development, say scientists.
The first-ever large-scale observation with human coding of babies’ vocalizations using all-day home recordings suggests they actively engaged in noisemaking play and sound practice.
The American and Austrian research teams identified the most common baby phonation categories as vocants or vowel-like sounds; squeals; and growls.
They investigated whether babies group specific noises in a non-random way, which would suggest practice or play.
The team analyzed recordings from 130 English-learning, normally developing babies recorded all day in their own homes in their first year of life.
A total of 21 five-minute samples were randomly chosen from each baby recording.
The researchers categorized each vocalization made in every sample into vocants, squeals, and growls – as well as “other” sounds.
Study co-author Dr. HyunJoo Yoo said: “Forty percent of all analyzed squeals and growls appeared in significant clusters across all infants.
“Over 60 percent of the five-minute sessions showed a significant amount of clustering focusing on either squeals or growls, not both in one session.”
The findings, published in the journal PLoS One, also revealed that 87 percent of the babies showed at least one age where their recordings had “significant squeal clustering” and at least one age where their recordings had “significant growl clustering” – with none of the babies demonstrating no clustering.
The research team acknowledged that their sound categorizing approach, while enabling them to collect a large amount of data, likely “oversimplified” complexities and nuances in baby vocalizations.
But they say the dataset gathered was “sufficient” to see clear patterns in individual babies as well as across the entire group, suggesting a possible pathway for language development warranting further investigation.
Dr. Yoo, an Assistant Professor at the University of Alabama, said: “Active vocal exploration and vocal category formation are fundamental to subsequent language development.”
She added: “The present study represents the first empirical investigation of early vocal category formation.
“Infants not only spontaneously produce speech-like vocalizations, but also actively explore and practice different types of vocalizations from the first months of life.”
