B
BABBLING AND EARLY WORDS
A child’s entrance into human society begins with the
onset of language development. Parents often ac-
knowledge this accomplishment upon hearing their
infant’s first words. Research on early language has
convinced scientists that the emergence of first words
is inseparable from important developmental mile-
stones that occur prior to the recording of these
words. Pre-speech vocalizations can be examined nar-
rowly within the verbal domain only, or can be ex-
plored in a wider scope as related to cognitive and
communicative developments that are established
during the first year of life. The study of pre-speech
vocalizations flourished during the last quarter of the
twentieth century. During the late 1970s and early
1980s, most efforts concentrated on describing the
sounds infants produce. In the 1990s, study of pre-
speech development expanded in several important
directions.
The Form of Infants’ Pre-Speech
Vocalizations
Pre-speech vocalizations are divided into reflex-
ive vocalizations (e.g., cries, coughs, hiccups), which
are related to the baby’s physical state, and nonreflex-
ive vocalizations (e.g., cooing, playful productions,
yelling), which contain phonetic and syllabic features
of speech. Both vowels and consonants appear in
nonreflexive vocalizations, and the most prevalent
syllable structure is a consonant followed by a vowel
(CV; e.g., \ba\, \du\, \ke). The overall composition of
pre-speech vocalizations changes dramatically during
the first year of life. In the first six months, babies all
over the world sound alike. During this period, vowels
predominate and are supported by prolonged back
consonants (e.g., \k\, \g\). During the next six months,
the sound repertoire significantly expands, with a
marked shift toward more frontal consonants. John
Locke reported in 1993 that, by their first birthday,
American English-speaking infants produce stops
(\p\, \b\, \t\, \d\, \k\, \g\), nasals (\m\, \n\), and glides
(\w\, \j\).Stages in the Development of Pre-Speech
Vocalizations
Developmental stages of pre-speech vocalizations
(e.g., as described by Carol Stoel-Gammon in 1998)
are not discrete, and vocalizations from previous
stages continue to be uttered subsequently. Novel
emergent behaviors define the beginning of a new
stage. Ages are assigned to each stage as estimates
only, because children differ greatly regarding the
timing for recording milestones of early language de-
velopment.
The first stage (from zero to two months), phona-
tion, is characterized mainly by fussing, crying, sneez-
ing, and burping, which bear little resemblance to
adult speech. The second stage (at two to three
months), cooing, begins when back vowels and nasals
appear together with velar consonants (e.g., \gu\,
\ku\). Cooing differs in its acoustic characteristics
from adult vocalizations and is recorded mainly45