Communication
Blows raspberries
Typical Timing & Development Window
Starts
20
wk avg
Median
24
wk
Std dev
±3
wk
Flag
28
wk
Visual Timeline & Milestone Benchmarks
Typical range (68% of babies)
Earliest typical start
Median milestone age
Pediatrician check-in flag
What these numbers mean
Starts
~wk 20
The average age babies first begin showing early signs of this skill. Before this, it's simply too early — there's nothing to worry about.
Median
wk 24
The midpoint age: half of babies have reached this milestone by here, half a little later. It's a typical target, not a deadline.
Std dev
±3 wk
How spread out the timing is. About two-thirds of babies achieve it within one standard deviation of the median (the shaded band, wk 21–27). Wide bands mean a normal range of variation.
Flag
wk 28
A gentle check-in point. If your baby hasn't shown this by around here, it can be worth mentioning to your pediatrician — most often it's still perfectly fine, just later.
About this milestone
The infant produces bilabial trills (raspberries) as playful oral motor practice.
What to try & how to support
- 1. Imitate the sound and encourage by making it back to them.
What to avoid & gentle reminders
- 1. Avoid forcing oral movements; keep play gentle and fun.