Is my child’s language development on track? That depends on who you ask.

Parents are often the first to suspect a language delay in their children, and when that parental instinct kicks in, the first thing many of us do is search for answers on google. But anyone who has looked up speech and language development online will tell you that a simple query returns lots of different sources of information. Adding to the confusion, a lot of those sources define “normal” development differently. Sometimes looking at just two different sources can lead to conflicting information.

It can feel complicated because there is no “single source of truth” for speech and language development, and parents, pediatricians and speech-language pathologists might all look at a different set of milestones. When you’re trying to find straight answers, this can be frustrating, to say the least.

Busy parents need answers, but there is a lot of confusion about what’s normal. How much do the milestones and red flags differ between sources, and what does this mean for spotting language delays and taking action at the right time? To help shed some light on the topic, we did a deep dive into the various developmental milestones to better understand how they vary.

What do speech-language milestones look like for the average child?

We compared the most common milestones for children up until 24 months in these prominent sources used by pediatricians and speech-language pathologists:

Centers for Disease Control (CDC), endorsed by the American Academy of Pediatrics (AAP)
American Academy of Family Physicians (AAFP)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Nipissing District Developmental Screen (NDDS) checklist
American Speech-Language-Hearing Association (ASHA)
Speech, Language, Audiology Canada (SAC)

The most common milestones tend to follow in the same order across sources, but the age ranges vary substantially. Take the example of a 10-month-old, who is babbling in single syllables (e.g., ‘ba’, ‘da’), but not babbling with reduplicated strings (e.g., ‘mama’) yet. Is this a cause for concern? A red flag? Or just normal variability? As we see below, the answer depends on the source.

The milestones above are the most common ones across different sources. The darker the color of the blue ribbons, the more sources agree on a particular time window [1]. While the exact wording for each can differ slightly, this is the guidance for what is typical at each age. But, some sources are meant to serve as a general description of the average child, with a range of variability, while others say that missing any of the milestones is a cause for concern.

When sources say different things, this can trigger anxiety for parents—especially if they are using a different source than their pediatrician to draw conclusions about their child’s development. Hoping to find some clarity, we zeroed in on sources that highlight red flags or delays where parents are advised to immediately consult with their pediatrician.

Moving from milestones to red flags

If you suspect your child is missing milestones, it’s only natural to wonder: now what? Some of the sources (including the CDC, ASHA, AAFP, NDDS and the Hanen Centre, a prominent speech-language pathology resource in Canada) say that action should be taken if any of these red flags are present. Parents are told to “follow up with a healthcare professional” if their child misses any items on the NDDS checklist—while the red flags on the AAFP list indicate the “need for immediate speech-language evaluation.” And, the recently updated CDC guidelines mean that a child missing any of the milestones is considered at risk of developmental delay. Below, we show the variation between the red flags [2].

We find the same issue with red flags that we found with milestones: all of them are either inconsistent across the different sources or inconsistent in the age ranges. Here’s where the confusion comes in: if a child is not yet babbling at 9 months, this would be considered a cause for concern by speech-language pathologists following ASHA’s guidelines—but probably not by parents or physicians following the CDC guidelines. A few of the red flags use the same or very similar language, but apply to different skills. And while speech-language pathologists might be able to tell the difference between normal variability and a true language delay, this might not be completely clear to parents—especially when they consult different sources with different guidelines.

What does this all mean for parents?

When parents, pediatricians and speech-language pathologists rely on different information, it can create a lot of confusion. The most important thing for parents to know is that speech and language development is complex. There is no single source of truth, and it’s okay not to have the answers. If you aren’t sure when it’s the right time to raise an issue with your baby’s doctor, you are not alone.

When the sources don’t agree, it’s all the more important to trust your intuition. You know your child better than anyone, and your perspective is invaluable. If the guidelines have left you wondering whether or not your child is meeting the milestones, get help from your doctor or a trained speech-language pathologist who can assess their unique abilities in a holistic way. There are lots of different factors that can contribute to why you might feel your child is not meeting their milestones—and it’s important to look at their skills in a broader context of their overall development, family history and more. And if you’re not ready to speak to someone about it, that’s okay, too. Know that there are different ways to get support, including simple strategies that you can use during your day while playing with your little one. Babbly is one way to access these strategies, and by recording and analyzing your baby’s voice in the app, you can find suggestions that are unique to your child’s skills.

Footnotes

Most sources provide time ranges for different milestones, while others list skills present at each age. For the latter, we assumed that the start of the time window was the last age marker at which a skill was not present and the end of the time window was the most advanced age at which a skill was mentioned.
Some sources have red flags for age ranges and others have individual age cut-offs. Wherever a red flag was present at a given age marker (e.g. 18 months), but not the preceding age marker (e.g. 15 months), we put the skill between the two markers. Wherever a single marker is present in the figure, this indicates that no preceding age was given.