Baby Language Development: From First Coos to First Words

Language development is one of the most fascinating aspects of your baby’s growth. Long before your baby says their first recognizable word, a complex foundation of listening, understanding, and vocalization is being built. From those first adorable coos at two months to stringing two-word phrases together as a toddler, each stage builds on the one before in a beautifully orchestrated progression.

Understanding the typical trajectory of language development helps you appreciate each stage, provides tools for encouraging your baby’s communication skills, and alerts you to potential concerns that warrant professional attention.

How Language Development Works: Receptive vs. Expressive Language

Before exploring the timeline, it is important to understand that language has two components:

• Receptive language refers to what your baby understands. Babies comprehend far more than they can express. A 10-month-old may understand dozens of words and phrases but say none of them yet.
• Expressive language refers to what your baby produces — the sounds, words, and eventually sentences they use to communicate.

Receptive language consistently runs ahead of expressive language throughout childhood. This is why your baby can follow the instruction “give me the ball” months before they can say the word “ball.”

Language Milestones by Age

Birth to 2 Months: The Listening Phase

Even in the womb, your baby was already listening. Newborns show a clear preference for their mother’s voice and for the language they heard most during pregnancy.

What to expect:

• Startles at loud or sudden noises
• Calms when hearing a familiar voice
• Cries as primary communication (different cries for hunger, discomfort, fatigue)
• Makes small throaty sounds and reflexive vocalizations
• Shows preference for speech sounds over non-speech sounds
• Recognizes caregiver voices and may turn toward them

What is happening in the brain: Newborns can already distinguish between the phonemes (individual sounds) of their native language and other languages. Brain imaging studies show that the auditory cortex is actively processing and categorizing speech sounds from the earliest days of life.

2-3 Months: The Cooing Stage

The cooing stage marks your baby’s first intentional vocalizations and the beginning of “conversational” exchanges.

What to expect:

• Produces vowel-like sounds: “aah,” “ooh,” “eee”
• Coos in response to your voice (early turn-taking)
• Makes pleasure sounds when content
• Begins to smile in response to voices
• Different cries for different needs become more distinguishable
• May quiet down when spoken to directly

What is happening in the brain: Your baby is experimenting with their vocal apparatus and discovering how to produce sounds intentionally. When you respond to their coos, you are teaching the fundamental structure of conversation: I talk, you listen; you talk, I listen.

4-6 Months: The Babbling Begins

This is when vocalizations start to sound more speech-like, and babies become vocal experimenters.

What to expect:

• Marginal babbling (4-5 months): Consonant-like sounds appear, often combined with vowels in single syllables (“ba,” “da,” “ga”)
• Canonical babbling (5-6 months): Repeated syllable strings emerge (“bababa,” “mamama,” “dadada”)
• Blows raspberries and makes other playful sounds
• Varies pitch and volume — may squeal with delight or growl experimentally
• Responds to changes in your tone of voice
• Turns toward sounds and voices
• Babbles when looking at toys or in the mirror
• May babble in what sounds like conversational patterns with rising and falling intonation

What is happening in the brain: Between 4 and 6 months, babies begin to narrow their focus to the sounds of their native language. A 4-month-old can distinguish sounds from any world language, but by 10-12 months, this ability fades for non-native sounds — a process called perceptual narrowing. This is one reason early bilingual exposure matters.

6-9 Months: Babbling Gets Complex

Babbling becomes more varied and more closely resembles the rhythms and patterns of real speech.

What to expect:

• Produces varied babbling with multiple consonant-vowel combinations (“baga,” “mada”)
• Babbling takes on the intonation patterns of the native language (sounds like sentences without real words)
• Responds to own name consistently
• Understands “no” (even if they do not always comply)
• Recognizes common words like “bottle,” “mama,” “daddy,” “bye-bye”
• Begins to use gestures: reaching with arms up to be picked up
• May point at objects of interest (by 9 months)
• Participates in back-and-forth vocal games
• Uses babbling to get attention

What is happening in the brain: The brain is rapidly mapping sounds to meanings. Your baby is building a mental dictionary of words they understand even though they cannot say them yet. Joint attention (when you and your baby look at the same thing together) becomes a critical driver of word learning.

9-12 Months: First Words Emerge

This is the period when babbling transitions to intentional communication, and first true words typically appear.

What to expect:

• First words usually appear between 10 and 14 months
• Common first words include “mama,” “dada,” “no,” “uh-oh,” “bye-bye,” and names of pets or siblings
• Uses gestures extensively: pointing, waving, shaking head “no,” reaching
• Understands simple instructions, especially when accompanied by gestures (“Give me the cup,” “Where’s the dog?”)
• May say one to three words by 12 months
• Uses babbling with real-word-like intonation (jargon babbling)
• Imitates speech sounds and simple words
• Points to request objects or to share interest (proto-declarative pointing)
• Understands 50 or more words even though they may only say a few

What is happening in the brain: The connection between the sound of a word and its meaning is solidifying. The brain’s language areas (Broca’s area and Wernicke’s area) are increasingly specialized. Gestures at this age are a strong predictor of later language ability.

12-18 Months: The Vocabulary Explosion Begins

After those first words, vocabulary growth accelerates. Most toddlers acquire new words slowly at first, then experience a rapid acceleration often called the “vocabulary explosion” or “word spurt.”

What to expect:

• Vocabulary grows from about 3-5 words at 12 months to 20-50 words by 18 months
• Uses single words to express complete ideas (“up” means “pick me up,” “juice” means “I want juice”)
• Follows one-step directions without gestures (“Bring me your shoes”)
• Points to familiar objects in books when named
• Points to body parts when asked
• Uses “no” and head shaking emphatically
• Imitates words they hear in conversation
• Begins to use words more than gestures

18-24 Months: Two-Word Combinations

The period from 18 to 24 months brings one of the most exciting language developments: combining words into mini-sentences.

What to expect:

• Vocabulary grows rapidly to 200-300 words by 24 months
• Two-word combinations emerge: “more milk,” “daddy go,” “big dog,” “all gone”
• Follows two-step directions (“Pick up the ball and bring it to me”)
• Points to pictures in books and names them
• Uses pronouns (me, my, mine) though not always correctly
• Asks simple questions (“What’s that?” “Where go?”)
• Strangers can understand about 50% of what the child says by 24 months
• Names familiar objects and people
• Begins to use words for feelings (“happy,” “ow”)

How to Encourage Your Baby’s Language Development

Research consistently shows that the quantity and quality of language input a baby receives has a profound impact on language development. Here are evidence-based strategies:

Talk, Talk, Talk

• Narrate your day: Describe what you are doing as you do it. “Now I’m putting on your socks. One sock on the left foot, one sock on the right foot.”
• Describe what your baby is doing: “You’re stacking the blocks! You put the red one on top.”
• Use parentese: The sing-song, higher-pitched, slower speech style (also called infant-directed speech) that adults naturally use with babies is not baby talk — it is a powerful language-teaching tool. Research shows babies pay more attention to and learn more from parentese than from adult-directed speech.
• Expand on your baby’s communications: If your baby says “dog,” respond with “Yes, that’s a big brown dog! The dog is running.”

Read Together Every Day

Reading aloud is one of the most effective ways to build language skills. The AAP recommends reading to babies from birth.

• Board books with simple pictures work best for the youngest babies
• Point to pictures and name them
• Let your baby hold and explore the book (mouthing is fine)
• Ask questions as your child gets older: “Where is the cat? Can you find the cat?”
• Follow your baby’s interest rather than insisting on reading every page
• Make it a daily routine — bedtime reading is a classic tradition for good reason

Respond and Take Turns

• Respond to babbling as if it were meaningful speech. Pause after your baby babbles and then respond: “Oh really? Tell me more about that!”
• Wait for your baby’s response after you say something. This teaches conversational turn-taking.
• Imitate your baby’s sounds — this validates their communication attempts and encourages more vocalization.

Sing Songs and Play Language Games

• Nursery rhymes and songs teach rhythm, rhyme, and language patterns
• Finger plays like “Itsy Bitsy Spider” and “Pat-a-Cake” combine language with movement
• Peek-a-boo teaches anticipation and social communication
• Naming games (“Where’s your nose? Where are your toes?”) build vocabulary

Bilingual Baby Development

Many families wonder whether raising a baby with two or more languages will cause confusion or delays. The research is clear: bilingualism does not cause language delay and offers significant cognitive benefits.

Key Facts About Bilingual Language Development

• Bilingual babies hit language milestones at the same ages as monolingual babies when you consider their total vocabulary across both languages
• Bilingual babies may have a smaller vocabulary in each individual language compared to monolingual peers, but their combined vocabulary across languages is equal to or greater than monolingual children
• Code-mixing (switching between languages within a sentence) is a normal and sophisticated linguistic behavior, not a sign of confusion
• The cognitive benefits of bilingualism include enhanced executive function, better attention control, and increased cognitive flexibility
• The best approach is one parent, one language (OPOL) or consistent language use by context (e.g., one language at home, another at school), though bilingual families use many successful strategies

Tips for Raising a Bilingual Baby

• Start early — babies are primed to learn multiple languages from birth
• Ensure your baby hears each language from a fluent speaker (not just from screens)
• Be consistent with your chosen language strategy
• Read books and sing songs in both languages
• Do not worry about code-mixing — it is normal and healthy
• Ignore well-meaning but incorrect advice that bilingualism will confuse your baby

Screen Time and Language Development

The AAP recommends avoiding screen time (other than video chatting) for children under 18 months. This recommendation is grounded in research showing that:

• Babies learn language best from live interaction, not from screens. A classic study by Patricia Kuhl showed that babies exposed to a foreign language via live interaction learned to distinguish the sounds, while those exposed through video or audio alone did not.
• Background television reduces the quantity and quality of parent-child interaction, which is the primary driver of language development.
• Video chatting is different: Interactive video calls with a responsive person (like a grandparent on FaceTime) can support language development because they maintain the critical element of social interaction.
• After 18 months, limited high-quality programming watched together with a caregiver (who talks about what is on screen) can be part of a healthy media diet.

Speech and Language Delay: Red Flags

While there is a wide range of normal in language development, certain signs warrant evaluation by a professional.

Red Flags by Age

By 6 months:

• Does not babble or make varied sounds
• Does not respond to sounds or voices
• Does not make eye contact during vocal exchanges

By 9 months:

• No babbling with consonant sounds (b, d, m, n)
• Does not respond to own name
• Does not show interest in back-and-forth vocal games
• Does not use gestures like reaching or waving

By 12 months:

• No single words (not even “mama” or “dada” used meaningfully)
• Does not point to objects
• Does not follow simple directions with gestures
• Does not use gestures to communicate

By 18 months:

• Fewer than 6 words
• Does not point to show you something interesting
• Does not notice or respond when you point at something
• Does not follow simple instructions without gestures
• Loss of previously acquired words or skills

By 24 months:

• Fewer than 50 words
• No two-word combinations
• Does not follow simple two-step instructions
• Strangers cannot understand any of the child’s speech
• Does not use words for purposes other than requesting

When to See a Speech-Language Pathologist

If you notice any of the red flags above, or if you have a gut feeling that something is not right with your child’s communication, do not wait. Early intervention is key.

A speech-language pathologist (SLP) can:

• Perform a comprehensive evaluation of receptive and expressive language skills
• Assess oral-motor function (how well the mouth muscles work for speech)
• Determine whether your child qualifies for Early Intervention services (free for children under 3)
• Provide parent coaching on strategies to stimulate language development at home
• Begin direct therapy if appropriate

You do not need a doctor’s referral to contact your state’s Early Intervention program. You can self-refer by calling your state’s Early Intervention office directly.

Risk Factors for Speech and Language Delays

Certain factors increase the likelihood of language delays:

• Family history of speech, language, or learning difficulties
• Premature birth or low birth weight
• Chronic ear infections (fluid in the ears can affect hearing and language exposure)
• Hearing loss or impairment
• Limited language exposure in the home environment
• Neurological conditions or genetic syndromes

The Role of Hearing in Language Development

Hearing is the foundation of spoken language development. Even mild hearing loss can significantly impact language acquisition.

Signs of Potential Hearing Issues

• Does not startle at loud sounds (newborn)
• Does not turn toward sounds (by 4-6 months)
• Does not respond to your voice when not looking at you
• Babbling does not progress or decreases over time
• Inconsistent response to sounds
• Frequent ear infections or fluid in the ears

All newborns should receive a hearing screening before leaving the hospital. If your baby did not pass the initial screening, follow up promptly. Even if the newborn screen was normal, hearing loss can develop later, so ongoing monitoring is important.

Frequently Asked Questions

Is it normal for my baby to say “dada” before “mama”?

Yes, this is very common and has nothing to do with who your baby prefers. The sounds “d” and “b” are among the earliest consonants babies produce because they are made with the lips and tongue tip in simple configurations. “Dada” and “baba” often appear before “mama” purely because of the mechanics of speech production, not because of any social preference.

My 15-month-old only says two words. Should I be concerned?

At 15 months, having two words is on the lower end of the typical range but is not necessarily a cause for alarm. The key is whether your child is making progress in other aspects of communication: Do they use gestures like pointing and waving? Do they understand many words? Do they make eye contact and engage socially? If your child is progressing in these areas, they may simply be a “late talker.” However, it is always appropriate to discuss concerns with your pediatrician.

Will watching educational videos help my baby learn to talk?

Research consistently shows that babies under 18 months learn language from live human interaction, not from screens. Even high-quality educational programs designed for babies do not teach language as effectively as face-to-face interaction. The best way to support your baby’s language development is through direct conversation, reading, singing, and responsive interaction.

Does baby sign language delay spoken language?

No. Research shows that teaching simple signs (like “more,” “milk,” “all done”) does not delay spoken language and may actually support it. Baby sign language gives babies a way to communicate before they can speak, which reduces frustration and builds communication skills. Most babies naturally drop signs as they acquire spoken words.

How can I tell if my baby’s language development is affected by being bilingual?

Bilingual language development follows the same timeline as monolingual development when you consider the child’s total vocabulary across both languages. A bilingual child’s vocabulary in each individual language may be smaller than a monolingual peer’s, but their combined vocabulary should be comparable. Red flags are the same regardless of the number of languages: no babbling by 9 months, no first words by 14-15 months, no two-word combinations by 24 months, and loss of previously acquired skills at any age.

References

• CDC Developmental Milestones - Centers for Disease Control and Prevention
• AAP Policy on Media Use in Children Under 2 - American Academy of Pediatrics
• NIDCD: Speech and Language Developmental Milestones - National Institute on Deafness and Other Communication Disorders
• WHO Child Development Indicators - World Health Organization
• HealthyChildren.org: Language Development - American Academy of Pediatrics
• ASHA: How Does Your Child Hear and Talk? - American Speech-Language-Hearing Association
• Kuhl, P. K. (2010). Brain Mechanisms in Early Language Acquisition. Neuron, 67(5), 713-727.

Written by

Dr. Michael Torres

Board-Certified Pediatrician, Medical Reviewer

Dr. Torres is a board-certified pediatrician with 12 years of experience in infant and toddler care. He serves as medical reviewer for Baby Care Guide, ensuring all content reflects current AAP guidelines and evidence-based pediatric practice.