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Normal Speech and Language Development

Language is defined as a symbolic system for the storage and exchange of information. Language consists of auditory expressive ability (speech), receptive ability (listening comprehension), and visual communication (gestures).

Normal Speech and Language Development

Auditory Expressive Language Development

In the first 4 to 6 weeks, the earliest sounds consist of cooing.

In the first few months, bilabial sounds begin, consisting of blowing bubbles or the "raspberry."

By 5 months, laughing and monosyllables appear.

Between 6 and 8 months, infants begin polysyllabic babbling, consisting of the same syllable repeated.

By 9 months, infants sporadically say "mama" or "dada" without knowing the meaning of these sounds.

By 10 months of age, infants use "mama" and "dada" consistently to label the appropriate parent.

By 12 months, infants acquire one or two words.

During the second year of life, vocabulary growth velocity accelerates, starting at one new word per week at 12 months of age and increasing to one or more new words per day by 24.

By 18 to 20 months, a toddler should be using a minimum of 20 words; the 24-month-old should have a vocabulary of at least 50 words.

Early during the second year of life toddlers produce jargon, consisting of strings of different sounds, with rising and falling, speech-like inflection.

These speech inflection patterns of are referred to as prosody.

By 24 months of age, toddlers are producing two-word phrases, such as "want milk!" Memorized phrases, such as "All gone" are not considered two-word phrases.

In the second year of life, pronouns appear ("me" and "you").

Third Year. Vocabulary growth velocity continues to accelerate, reaching a rate of several new words per day. If a 30-month-old's vocabulary should be too large.

By 24 to 30 months, children develop "telegraphic" speech.

Increased intelligibility develops in toddlers.

Auditory Receptive Language Development

Newborn infants respond to vocal stimuli by eye widening or changes in sucking rate.

The 2- or 3-month-old infant watches and listens intently to adults.

Visual Language Development

During the first few weeks, the infant will display alert visual fixation.

By 4 to 6 weeks, a social smile appears.

By age 4 to 5 months, the infant will turn towards.

Classification of Speech and Language Disorders

Hearing Loss

One infant per thousand is born with bilateral, severe-to-profound hearing loss.

One third of congenital deafness is genetic in origin, one third is nongenetic, and one third is of unknown etiology. The most common nongenetic cause of deafness is fetal CMV infection.

Otitis media with effusion (OME) causes transient, mild-to-moderate hearing loss. Developmental language disorders (DLD) have an with increased frequency among infants.

Mental Retardation

Three percent of children are mentally retarded, and all children who are mentally retarded are language-delayed. Mental retardation (MR) is defined as significantly subaverage.

Intelligence that is "significantly subaverage" is defined as more than 2 standard deviations (SD) below the mean. "Mild" MR is defined as -2 to -3 SD. Intelligence tests are standardized to a mean score of 100, and mild MR is equivalent to an intelligence quotient (IQ) of 69 to 55. Moderate MR = -3 to -4 SD (IQ 54 to 40), severe MR = -4 to -5 SD (IQ 39 to 25).

Most mentally retarded children are mildly retarded, and most of these are normal biologically; their mild MR reflects low polygenic endowment for intelligence. Any child who has an IQ below 55 should be assumed to have an underlying pathologic process as the source.

Pathologic entities that cause MR include chromosomal and teratogenic disorders; sporadic syndromes of unknown etiology; perinatal events; and hypoxic, traumatic, infectious, or toxic postnatal insults.

Developmental Language Disorders (DLD)

DLD are disorders characterized by selective impairment of speech and/or language development. General intelligence is normal. DLD affects 5-10% of preschool children.

In the majority of cases, the etiology of DLD remains unknown; however, DLD can be caused by sex chromosome aneuploidy, fragile X syndrome, neonatal intracranial hemorrhage.

Autism

Autism manifests as delayed and deviant language development, impaired affective development, monotonously repetitious behaviors with an insistence on routines.

Autism can be caused by most of the same etiologies.

Stuttering

Physiologic disfluency is characterized by a transient loss of normal rate and rhythm of speech, and it is normal in children between 2 and 4 years of age. Physiologic disfluency involves repetition.

Stuttering, or dysfluency, involves repetition of shorter speech segments ("I wu . . . wu . . . wwwwant to go home") or a complete inability to initiate a word, referred to as "blockage."

Dysarthria is caused by a physical impairment of the muscles of speech production. Dysarthria in children usually is encountered as one component of cerebral palsy (CP).

Clinical Evaluation of Speech and Language Disorders

Infants with hearing-impairment usually develop auditory expressive and receptive delay; visual language is normal. Deaf infants coo and babble normally until 6 months of age.

Mentally retarded children manifest delay in all language areas. Cooing and babbling may be reduced.