Language development changes rapidly during the first five years of life. The CDC describes milestones as skills that most children—at least 75%—can do by a specific age, while the NIDCD describes the first three years as the most intensive period for acquiring speech and language skills. Together, these measures show both the typical sequence of communication growth and the scale of speech, language, and voice disorders among U.S. children.
Contents
- How to read language development statistics
- Language milestones from birth to 12 months
- Communication growth from 15 months to 3 years
- Language skills from ages 4 to 5
- How common are communication disorders?
- Stuttering and developmental language disorder
- Intervention, screening, and support
How to read language development statistics
Milestone statistics describe what most children can do by an age, not a fixed schedule that every child follows. For example, the CDC’s milestone definition uses a threshold of 75% or more. A child who has not reached a milestone is not diagnosed by that fact alone, but the information can help families and professionals decide when to discuss a concern.
The NIDCD emphasizes that speech and language skills develop best through consistent exposure to other people’s speech and language. Newborns recognize important sounds, including the voice of a mother or primary caretaker, and crying is an early communication signal that can bring food, comfort, and companionship. By 6 months, most babies recognize the basic sounds of their native language. The NIDCD also notes that when critical periods pass without language exposure, learning language later becomes more difficult.
These facts describe development in general terms rather than providing a single prediction for an individual child. The NIDCD also distinguishes between receptive language—the ability to understand what others say—and expressive language—the ability to share thoughts. Trouble understanding speech can indicate a receptive language disorder, while difficulty expressing thoughts can indicate an expressive language disorder. Hearing loss can cause speech and language delay, which is why a hearing test is often included in a speech and language evaluation.
Language milestones from birth to 12 months
The first year includes a progression from reacting to sounds to using intentional social communication. The CDC reports these milestones for most babies:
| Age | Communication milestone | Source |
|---|---|---|
| 2 months | Makes sounds other than crying; reacts to loud sounds | CDC Milestones by 2 Months |
| 4 months | Coos, makes sounds back when spoken to, and turns toward a voice | CDC Milestones by 4 Months |
| 6 months | Takes turns making sounds, blows raspberries, and squeals | CDC Milestones by 6 Months |
| 9 months | Makes many different sounds, such as “mamamama” and “bababababa” | CDC Milestones by 9 Months |
| 1 year | Waves goodbye, uses a special name for a parent, and understands “no” | CDC Milestones by 1 Year |
At 2 months, the milestones focus on vocalization and response: most babies make sounds other than crying and react to loud sounds. At 4 months, most babies produce cooing sounds such as “oooo” and “aahh,” respond vocally when spoken to, and turn their heads toward a voice. At 6 months, the exchange becomes more interactive as babies take turns making sounds with caregivers.
By 9 months, most babies make repeated sound patterns. By 1 year, communication includes gestures, names, and comprehension: most babies wave “bye-bye,” call a parent “mama,” “dada,” or another special name, and understand the word “no.” These milestones combine sounds, social interaction, gestures, and understanding rather than measuring vocabulary alone.
Communication growth from 15 months to 3 years
Between 15 months and 3 years, the CDC milestones move from single words and gestures toward combinations, questions, and conversation. At 15 months, most children try to say one or two words besides “mama” or “dada.” They also look at a familiar object when it is named, follow directions given with both gestures and words, and point to ask for something or get help.
At 18 months, most children try to say three or more words besides “mama” or “dada.” Most can also follow a one-step direction without gestures. These measures connect expressive language with receptive language: children are both attempting more words and responding to spoken instructions.
At age 2, most children point to things in a book when asked, say at least two words together, point to at least two body parts when asked, and use more gestures than just waving and pointing. The age-two milestones therefore include word combinations, understanding, shared attention, and a broader set of communicative gestures.
At 30 months, most children say about 50 words. Most also say two or more words together with one action word, name things in a book when asked, and use words such as “I,” “me,” or “we.” The CDC’s 30-month milestone is especially useful for showing that language growth includes vocabulary size, sentence structure, book-related naming, and early pronoun use.
By age 3, most children talk in conversation using at least two back-and-forth exchanges. Most ask who, what, where, or why questions; say what action is happening in a picture or book when asked; and say their first name when asked. The CDC also reports that most 3-year-olds are understood by others most of the time.
Language skills from ages 4 to 5
The CDC’s later milestones emphasize longer speech, storytelling, comprehension, and sustained conversation. At age 4, most children say sentences with four or more words. Most also say some words from a song, story, or nursery rhyme, talk about at least one thing that happened during their day, and answer simple questions about what objects are for.
At age 5, most children tell a story with at least two events and answer simple questions about a book or story after hearing it. Most keep a conversation going with more than three back-and-forth exchanges and use or recognize simple rhymes. Compared with the age-3 milestones, these measures place greater emphasis on narrative structure, listening comprehension, conversational persistence, and early sound awareness.
The NIDCD cautions that development does not look identical for every child. Some children with developmental language disorder may not begin to talk until their third or fourth year. A delayed first word is only one possible pattern; difficulties may instead involve understanding, expressing ideas, speech sounds, voice, or fluency.
How common are communication disorders?
The NIDCD reports that approximately 1 in 14, or 7.2%, of U.S. children ages 3–17 had a voice, speech, or language disorder in the past 12 months. The same source reports that prevalence was highest among children ages 3–6, at 10.8%. It was 8.8% for ages 7–10 and 4.3% for ages 11–17.
| Group | Reported prevalence or measure |
|---|---|
| U.S. children ages 3–17 with a voice, speech, or language disorder in the past 12 months | 7.2% |
| Ages 3–6 | 10.8% |
| Ages 7–10 | 8.8% |
| Ages 11–17 | 4.3% |
| Boys ages 3–17 | 9.1% |
| Girls ages 3–17 | 5.2% |
Source for the table: NIDCD Quick Statistics About Voice, Speech, Language.
The NIDCD reports a difference by sex in these U.S. estimates: boys ages 3–17 had a reported prevalence of 9.1%, compared with 5.2% for girls. Among children with a voice, speech, or language disorder, 33.9% of those ages 3–10 had multiple communication disorders, compared with 25.2% of those ages 11–17.
The reported prevalence also varied across racial and ethnic groups: 8.9% for Black children ages 3–17, 7.3% for White children, and 6.4% for Hispanic children. These figures describe the populations and age range reported by the NIDCD; they do not establish why the rates differ.
Speech disorders affected 5% of U.S. children ages 3–17 for a week or longer in the past 12 months. The NIDCD reports that speech sound disorders in young children have a prevalence of 8% to 9%, and that roughly 5% of children have noticeable speech disorders by first grade.
Stuttering and developmental language disorder
Stuttering is another communication statistic with a clear age pattern. The NIDCD reports that more than 3 million Americans—about 1%—stutter. Stuttering occurs most frequently in children ages 2–6. Boys are two to three times more likely than girls to stutter, and as many as 1 in 4 people who stutter will continue to stutter for life. These figures describe stuttering at the population level and do not predict an individual child’s outcome.
The NIDCD reports a prevalence of 7%, or about 1 in 14 children, for developmental language disorder. An earlier NIDCD page on specific language impairment reports that approximately 7% to 10% of children in kindergarten are affected. It also reports that approximately 2% to 3% of children with language impairment have an existing medical condition and/or intellectual disability.
Family history is reported in the same NIDCD material: 50% to 70% of children with specific language impairment have at least one family member with the disorder. The NIDCD also states that learning more than one language at a time does not cause specific language impairment and that its impact usually persists into adulthood.
Intervention, screening, and support
Among U.S. children ages 3–17 with a voice, speech, or language disorder, 59.7% received intervention services in the past year, according to the NIDCD Quick Statistics About Voice, Speech, Language. The reported percentages varied by group: 64.3% of White children, 51.7% of Hispanic children, and 49.9% of Black children with a disorder received intervention services.
The same source reports intervention services for 62.8% of boys and 53.9% of girls with a voice, speech, or language disorder. By problem type, services reached 67.6% of children with speech problems, 66.8% of children with language problems, and 22.8% of children with voice disorders. These percentages measure receipt of intervention services in the past year, not whether a child’s communication difficulty resolved.
The CDC recommends developmental screening at 9 months, 18 months, and 30 months using standardized, validated tools. The CDC recommends autism screening at 18 months and 24 months, or whenever a concern is raised. Screening schedules are opportunities to discuss development; they are not replacements for a professional evaluation when a caregiver or clinician has a concern.
For language specifically, evaluation can consider both understanding and expression, speech production, hearing, and communication in everyday settings. The NIDCD’s guidance on hearing tests is particularly relevant because hearing loss can contribute to speech and language delay. The combination of milestone tracking, screening, hearing assessment, and appropriate intervention gives families and professionals several ways to respond when a child’s communication development raises questions.