Version July 2025
| Age | Red flag | Type of skill |
| Birth or any age | Does not respond to sounds, particularly parent's/caregiver's voice | Receptive language |
| 6 to 9 months | Does not babble | Expressive language |
| 12 months | Does not use "mama," "dada," or "papa" to call parent | Expressive language |
| 15 months | Does not use specific single word or word approximation other than "mama," "dada," or "papa" to request or comment | Expressive language |
| Does not use a point to request something out of reach | Gestural communication | |
| 18 months | Does not have at least five words used spontaneously to make requests or to comment on or label objects (assessed by asking: "How does your child let you know what she wants?" or "What words does your child use to ask for things?") | Expressive language |
| Does not follow familiar one-step direction without gesture | Receptive language | |
| Does not point to something in order to share enjoyment or excitement with another person (joint attention) | Gestural communication | |
| 24 months | Uses fewer than 50 words | Expressive language |
| Does not combine two words together to create new meaning. (See caution below.)¶ | Expressive language |
* Typically the age at which 90% of typically developing children have attained the skill.
¶ Parents/caregivers may report stock phrases (eg, "let's go," "all done," "good job") or compound nouns ("dump truck," "Tyrannosaurus rex," "baby doll") as examples of this skill. These do not count as novel two-word combinations. Ask parents/caregivers for specific examples, and probe further if these types of examples are the only ones provided.
