Cooing
Most babies start making soft vowel sounds like "ooo" and "aah" in their first few months. In a study in four countries, half did so by about 1 month, and a review of earlier studies puts cooing at around 3 months.
How sure are we?
Not sure yet. Only one large study has measured this age so far, and studies describe these early sounds in different ways. How we know this
What it’s a sign of
Your baby is starting to use their voice for more than crying.
Studies describe early sounds in different ways. One large study asked parents when their baby first made vowel sounds (about 1 month); others describe cooing, a softer, more musical "ooo", at about 3 months. The CDC lists cooing at 4 months, using the age by which about 3 in 4 babies do it, rounded up to the next check-up.
We haven't yet read the classic studies that first described cooing, so the spread of ages isn't on this page yet.
A main source for the ages
Similarities and differences in child development from birth to age 3 years by sex and across four countries: a cross-sectional, observational study
Ilgi Ozturk Ertem, Vibha Krishnamurthy, Mphelekedzeni C. Mulaudzi, Yanina Sguassero, Hakan Balta, Ozlem Gulumser · 2018 · Lancet Global Health
- Children
- About 4,900 healthy children
- Where
- Argentina, India, South Africa and Turkey
- Ages
- Birth to 3½ years
- How
- Trained staff asked parents open questions about what their child could do, at health clinics
- What it found
- Found the age by which half of children reached more than 100 milestones. Most came at similar ages in all four countries, and for boys and girls. For example, half of children waved bye-bye by about 11 months and said a first word by about 9 months.
- Limits
- Only four countries and no rural areas, children from city clinics, and only healthy children (about half of those who came were left out for health reasons). It gives the age for half of children, not the full spread.
A main source for the ages
Canonical Babbling: A Marker for Earlier Identification of Late Detected Developmental Disorders?
Sigrun Lang, Katrin D. Bartl-Pokorny, Florian B. Pokorny, Dunia Garrido, Nivedita Mani, Annette V. Fox-Boyer, Dajie Zhang, Peter B. Marschik · 2019 · Current Developmental Disorders Reports
- Children
- A review of earlier studies
- Where
- Studies in many languages, including English, Dutch, Swedish, Spanish, German, Mandarin and Cantonese
- Ages
- Babies in their first year
- How
- Researchers summarised earlier studies of when babies start babbling
- What it found
- Says typically developing babies start babbling between about 5 and 10 months, at similar ages across many languages.
- Limits
- A summary of other studies, not new measurements. Its main focus is babies with particular conditions, which we don't cover.
A main source for the ages
Evidence-Informed Milestones for Developmental Surveillance Tools
Jennifer M. Zubler, Lisa D. Wiggins, Michelle M. Macias, Toni M. Whitaker, Judith S. Shaw, Jane K. Squires, Julie A. Pajek, Rebecca B. Wolf, Karnesha S. Slaughter, Amber S. Broughton, Krysta L. Gerndt, Bethany J. Mlodoch, Paul H. Lipkin · 2022 · Pediatrics
- Children
- A review of 34 studies and common checklists, not one group of children
- Where
- Studies from many countries (14 of the 24 with age data were from countries where English isn't the main language)
- Ages
- 2 months to 5 years
- How
- Experts reviewed studies and checklists, then placed each milestone at the check-up age by which about 3 in 4 children do it
- What it found
- Places calling a parent "mama" or "dada" at 12 months, and saying 1 or 2 other words at 15 months. These are ages by which about 3 in 4 children have started, rounded up to a check-up age.
- Limits
- Experts' judgement set the ages, and some milestones rest on opinion rather than measured ages. The lists haven't been tested to see whether they help.
If you’re worried about your child, talk to your child and family health nurse or GP.
Last checked 2 November 2026