Most children develop speech at their own pace, but there are specific milestones at each age that help you tell the difference between a child who’s simply a late bloomer and one who would benefit from professional help. The clearest signal is when a child falls behind on benchmarks that at least 75% of children their age have already reached. Here’s how to know what to look for and when to act.
Speech Milestones by Age
The revised developmental checklists from the CDC are designed so that each milestone reflects what most children (75% or more) can do at a given age. If your child hasn’t hit these markers, it doesn’t automatically mean something is wrong, but it does mean the gap is worth paying attention to.
By 12 months, most children are babbling with varied sounds, using simple gestures like waving or pointing, and saying at least one or two words like “mama” or “dada” with meaning. Between 15 and 18 months, you should hear a small but growing vocabulary. In research studies, typically developing 18-month-olds spoke an average of about 120 words, while late talkers at the same age averaged around 20. Your child doesn’t need to hit 120, but a child who has fewer than 10 words at 18 months is on the low end of the spectrum and worth watching closely.
By age 2, a vocabulary explosion is underway. Typically developing children in one large study averaged nearly 400 words by 24 months and were starting to combine two words together (“more milk,” “daddy go”). Late talkers at the same age averaged about 160 words. Two-word combinations are a key milestone here. If your child isn’t putting words together by their second birthday, that’s one of the most commonly used triggers for a closer look.
By age 3, children are using short sentences, asking questions, and having simple conversations. By 4 to 5, they can tell a short story, follow multi-step directions, and be understood by most people they talk to.
How Much Should Strangers Understand?
One practical test is how well an unfamiliar person can understand your child. Parents naturally decode their child’s speech better than anyone, so the real benchmark is whether someone outside the family can follow along.
Research measuring how well unfamiliar listeners understand young children found that at 30 months, the median child was about 40% intelligible to a stranger. By 37 months (just over age 3), that rose to about 57%. By 47 months (close to age 4), the median reached about 78%. These numbers are lower than older guidelines that relied on parent reports, which estimated children were 50% intelligible at 22 months, 75% by age 3, and nearly 100% by age 4. The truth, when measured by actual strangers listening, is more conservative.
If people outside your household consistently can’t understand your 3-year-old, or your 4-year-old is still very difficult to follow, that’s a meaningful sign that speech therapy could help.
Sounds Your Child Should Be Making
Not every mispronunciation is a problem. Children master different consonant sounds on a predictable timeline, and some sounds are genuinely hard for young mouths to produce.
Between ages 2 and 3, children typically use the sounds k, g, f, t, d, and n. By 3 to 4, their speech is clear enough for family and friends to understand most of what they say, even if some sounds are still off. By 4 to 5, most sounds are in place, with a handful of exceptions: l, s, r, v, z, ch, sh, and th are the last to develop and may not fully arrive until age 6 or 7.
So if your 3-year-old says “wabbit” instead of “rabbit,” that’s completely normal. But if your 4-year-old is still dropping beginning consonants, substituting many sounds, or is hard for peers to understand during play, a speech evaluation is a reasonable next step.
Receptive vs. Expressive Delays
Speech and language problems fall into different categories, and the distinction matters because they call for different approaches.
Expressive language is what your child says. A child with an expressive delay may understand everything you tell them but have a limited vocabulary, struggle to form sentences, or have trouble finding words. These children often compensate with gestures and are clearly trying to communicate. Expressive delays are the most common type and often the first thing parents notice.
Receptive language is what your child understands. A receptive delay is typically more concerning because it means the child has difficulty processing what they hear. Signs include not following simple directions (“go get your shoes”), not responding to their name consistently, or seeming confused by questions that other children their age handle easily. Receptive delays are harder for parents to spot because the child may not “look” like they have a problem until demands for comprehension increase.
A child can have one or both types. If your child seems to not understand you (rather than simply ignoring you, which is its own challenge), that’s a stronger reason to seek evaluation sooner rather than later.
Red Flags That Go Beyond Late Talking
Some behaviors suggest the issue is more than a speech delay and may point to a broader developmental concern. These warrant bringing up with your pediatrician promptly:
- No gestures by 12 months. Pointing, waving, and reaching are pre-language skills. A child who isn’t gesturing is missing a building block that words are built on.
- Loss of skills. A child who was saying words or babbling and then stops is a red flag at any age.
- Limited social engagement. Not returning smiles, not making eye contact, preferring to play alone, or seeming unaware of other people in the room.
- Unusual responses to sensory input. Not reacting to pain typically, not noticing loud sounds, or seeming not to hear their name while clearly hearing other noises.
- Repetitive or scripted language. A child who can recite the alphabet or lines from a TV show but can’t use words to ask for something they want.
- Unusual object fixation. Strong interest in objects like flashlights or pens rather than age-appropriate toys.
These patterns can appear alongside speech delays and are among the early signs that screening for autism or other developmental conditions is appropriate. Autism screening is recommended at 18 and 24 months.
When Stuttering Needs Attention
Nearly all young children go through a phase of disfluent speech, typically between ages 2 and 5, where they repeat whole words (“I-I-I want that”) or restart sentences. This is a normal part of language development as their brains work faster than their mouths can keep up.
Stuttering becomes a concern when you hear frequent repetitions of parts of words or individual sounds (“b-b-b-ball”), prolonged sounds where the child seems stuck, or visible tension in the face or jaw while trying to speak. The frequency matters more than the type: fluent children and children who stutter produce the same kinds of disfluencies, but children who stutter do it significantly more often.
Many children who stutter in early childhood recover on their own, and recovery rates are high for those who primarily repeat whole words. But if stuttering persists beyond six months, is getting worse, or your child is showing frustration or avoidance around speaking, an evaluation with a speech-language pathologist is a good idea. Stuttering that continues past age 7 or 8 is more likely to persist into adulthood, so earlier intervention gives a better window.
How to Get an Evaluation
You don’t need to wait for your pediatrician to raise a concern. If something feels off, you can request a referral to a speech-language pathologist directly. Pediatricians use developmental screening tools at well-child visits (typically at 9, 18, and 30 months), but these are broad screens and can miss subtler delays.
For children under age 3, every state in the U.S. has an early intervention program funded under federal law. You can refer your own child for a free evaluation without needing a doctor’s referral. Search for your state’s early intervention program online or ask your pediatrician for the contact information. If your child qualifies, services are provided at low or no cost, often in your home.
For children 3 and older, your local public school district is required to evaluate children for speech and language services at no charge, regardless of whether the child is enrolled in that school. You can request this evaluation in writing.
What Speech Therapy Looks Like
For toddlers under 3, sessions are typically 30 minutes long. At this age, therapy is almost entirely play-based. The therapist works on the floor with your child, using toys, books, and games to build vocabulary, encourage sounds, and model language. Parents are coached on strategies to use throughout the day, which is often where the biggest gains happen.
Preschoolers ages 3 to 5 usually have sessions lasting 30 to 45 minutes, with a mix of structured activities and play. Younger children and those with shorter attention spans generally do better with shorter, more frequent sessions rather than one long weekly visit. Some children attend once a week, others twice. The frequency depends on the severity of the delay and how the child responds.
Progress varies widely. Some children with mild expressive delays catch up within a few months. Others with more complex language disorders may need therapy for a year or longer. The consistent finding across research is that earlier intervention leads to better outcomes, particularly for receptive language problems and delays that co-occur with other developmental concerns.