Speech and Language Development: Birth to 6 Years

✓ Reviewed against CDC Learn the Signs. Act Early., AAP HealthyChildren, ASHA developmental milestones, NIDCDEvidence level ALast reviewed July 1, 2026Published July 1, 2026

Speech and language development is how children learn to make sounds and use words to communicate, unfolding in predictable stages from birth to about age 6. Speech is how sounds are produced; language is understanding and using words. Most children follow the same sequence — at their own pace.

What speech and language development means

Speech and language development is the process by which children learn to make sounds and use words to communicate. It begins at birth — with a baby’s first cries and coos — and unfolds in a predictable sequence through about age 6, when most children speak clearly and hold real conversations.^1,5

Every child moves through this sequence at their own pace. Development milestones describe what most children do by a given age; ASHA’s checklists, for example, list the age by which roughly 75% of children show each skill. They are a roadmap, not a stopwatch.²

📝

This page is a starting point

Here you’ll find the big picture from birth to 6. For a deeper look at any single age, follow the links to our by-age milestone guides and to First Words.

Speech vs. language — the key difference

People use “speech” and “language” interchangeably, but to a speech-language pathologist they are two different things — and a child can be strong in one while behind in the other.¹

Speech is how sounds are produced — articulation (saying sounds clearly), voice, and fluency (smooth, un-stuttered talking).
Language is the meaning behind the words — the vocabulary and grammar a child understands and uses to share ideas.

Because they develop somewhat separately, a toddler might have plenty of words but be hard to understand, or speak very clearly but use few words. Looking at both is how professionals tell the difference between a speech sound difficulty and a language delay.^1,5

How speech and language develop from birth to 6 years

Development follows a recognizable arc. In the first year, babies coo, then babble, then say their first words. In the second year, single words become two-word combinations. From ages 3 to 6, sentences grow longer and grammar, storytelling, and conversation come together.^5,2

Understanding almost always runs ahead of talking. Long before a baby says “ball,” they turn to the word, and long before a toddler forms sentences, they follow simple directions. That gap between understanding and speaking is normal and expected.⁵

💡

Watch the trend, not the moment

A single quiet week says little. What matters is steady forward movement — new sounds, new words, and new ways of putting them together over the months.

Stages of speech and language development by age (0–6)

Here are widely used milestones from the CDC and ASHA across the birth-to-6 years. Use the table for the overview, then follow the links for a full guide to each age.^7,2

Typical speech & language development by age (CDC “Learn the Signs. Act Early.” and ASHA).
Age	What most children do
Birth–12 months	Coos and babbles; responds to their name; by around 12 months says a first word or two and uses gestures like waving.
18 months	Says several single words; tries to copy words; points to show you something.
2 years	Puts at least two words together (“more milk”); uses many words; follows simple directions.
3 years	Talks well enough for strangers to understand most of the time; uses short sentences and asks “why.”
4 years	Says sentences of four or more words; tells you about something that happened; most speech is clear.
5–6 years	Tells a short story; holds a back-and-forth conversation; speaks in full, mostly grammatical sentences.

Typical speech & language development by age (CDC “Learn the Signs. Act Early.” and ASHA).^{7,8,9,10,11,12}

Want the detail for a specific age? See our full guides — First Words for the earliest stage, then Speech at 2 Years, and the wider Speech Milestones by Age roadmap for 3, 4, 5, and 6.^3,4

Free Speech Milestone Checker

Check your child’s speech against milestones in 2 minutes.

Try it free →

Receptive vs. expressive language

Language itself has two sides, and both matter when you’re gauging whether a child is on track.¹

Receptive language — what a child understands: following directions, pointing to named objects, answering questions.
Expressive language — what a child produces: the words, phrases, and sentences they use to communicate.

Receptive skills typically develop ahead of expressive ones, so most children understand far more than they can say. A child who understands well but says little may be a “late talker”; a child who struggles to understand is a stronger reason to seek an evaluation.^5,14

The sound-acquisition sequence

Separate from words and sentences, individual speech sounds come online in a fairly fixed order. A large review of U.S. children found that early sounds are in place by age 3, most mid sounds by 4, and the trickiest sounds between 5 and 6.¹⁵

Age by which ~90% of U.S. children produce each consonant (Crowe & McLeod, 2020).
By age	Consonants typically mastered
2 years	m, b, n, p, h, w, d
3 years	g, k, f, t, “ng”, y
4 years	v, “j”, s, “ch”, l, “sh”, z
5 years	r, voiced “th”, “zh”
6 years	voiceless “th”

Age by which ~90% of U.S. children produce each consonant (Crowe & McLeod, 2020).¹⁵

💡

So “r” and “th” take longest

R, S, and the “th” sounds are among the very last to develop. A 5-year-old still working on “r” is often right on schedule — overall intelligibility matters more than any single sound.

What influences speech and language development

Development is shaped by both a child’s biology and the world around them. A few factors carry the most weight:⁵

Hearing — the single most important factor. Even temporary hearing loss from frequent ear infections can slow speech and language, so hearing is checked first when there’s a concern.
Everyday language exposure — talking, reading, singing, and responsive back-and-forth conversation feed vocabulary and grammar; limited interaction can slow them.
Overall development and health — motor, cognitive, and social growth are intertwined with communication.
Bilingualism — growing up with two languages does not cause a delay. Bilingual children reach communication milestones on a typical timetable.

🩺

Check hearing first

Because hearing underlies everything else in speech and language, any evaluation for a suspected delay should start by ruling out a hearing problem.

How to support development at home

You don’t need special training to be your child’s best language partner — everyday moments are the practice. Simple, responsive habits do the most:¹³

Narrate your day — name what you see, do, and touch as you go.
Follow your child’s lead and respond to their sounds, words, and gestures.
Read together daily, pausing to talk about the pictures.
Expand what they say — when they say “dog,” you say “Yes, a big brown dog!”
Give real back-and-forth turns and wait for a response.

For children working on specific sounds, short, frequent, focused practice is what drives progress. SpeechStep turns milestone goals into quick, guided sessions with instant, encouraging feedback — at home, and as a first step if you’re unsure whether to seek an evaluation.

Signs development may be off track — and what to do

1 in 12U.S. children ages 3–17 has a disorder of voice, speech, language, or swallowing.⁶

Milestones are a guide, not a deadline — but reaching them much later than other children, or losing skills already gained, can be the earliest sign of a delay.^2,5

No babbling or gestures (like pointing or waving) by around 12 months.
Not putting two words together by age 2.
Hard for unfamiliar people to understand by age 3.
Trouble understanding or following simple directions for their age.
Lost speech or language skills they previously had.

⚠️

Act early — don’t “wait and see”

If a milestone is missed, your child loses skills, or you’re simply worried, talk to your pediatrician and ask about developmental screening. Under age 3, contact an early-intervention program for a free evaluation; at age 3 and older, your local school district can evaluate. Acting early leads to better outcomes.

An evaluation is free and low-pressure, and catching a delay early — rather than waiting — gives your child the best head start, because even mild delays can affect later reading and learning.^14,10

Frequently asked questions

What is the difference between speech and language development?＋

Speech is how a child physically produces sounds — the articulation, voice, and fluency of talking. Language is the words and grammar a child understands and uses to share meaning. A child can be developing well in one and behind in the other, which is why speech-language pathologists look at both.

What are the stages of speech and language development from 0 to 6 years?＋

Development moves through predictable stages: cooing and babbling in the first year, first words around 12 months, two-word combinations by age 2, short sentences by age 3, longer sentences and simple stories by ages 4–5, and clear, conversational, grammatically complete speech by age 6. Children move through the same sequence at their own pace.

What is the difference between receptive and expressive language?＋

Receptive language is how well a child understands what is said — following directions, pointing to named pictures, answering questions. Expressive language is the words, phrases, and sentences a child produces to communicate. Understanding usually develops ahead of talking, so a child often comprehends far more than they can say.

What factors affect a child’s speech and language development?＋

Hearing is the biggest single factor — even repeated ear infections can slow things down. Rich everyday talk, reading, and responsive back-and-forth conversation help language grow, while limited exposure can slow it. Growing up bilingual does not cause a delay; bilingual children reach communication milestones on a typical timetable.

How do I know if my child’s speech development is on track, and what should I do if I’m worried?＋

Compare your child with widely used milestones: two words together by age 2, understood by strangers most of the time by age 3, short stories by ages 4–5. If your child is well behind, has lost skills, or you are simply worried, talk to your pediatrician and ask about developmental screening. Under age 3 you can contact an early-intervention program; at age 3 and older your school district can evaluate. Acting early leads to better outcomes.