How to be Cautious When Using Speech Development Norm Charts

What you need to know when using speech development norm charts.

Development charts are very useful, but it is important to use and read them correctly. For several reasons, it is critical to be cautious when using speech norms.

Speech therapy development norm charts serve as great guides for development, as well as assessing skills and structuring therapy. They are especially beneficial for parents to gauge their child’s development and if they need to seek out intervention.

But it is easy to use speech therapy norms charts as a standalone way of assessing a child when, in reality, they should be one piece of the puzzle. It is also critical to interpret the data provided correctly regarding averages and milestones and, at times, to understand how the studies were conducted.

Commonly asked questions and what to keep in mind when reviewing norm charts:

Why are norms only one piece of the puzzle when assessing a child?

While we may want charts showing “normal” or “typical” development, this doesn’t exist. Given the wide range of variability, assigning a rigid expectation timeline can be harmful. We don’t control the numerous factors affecting a child’s development. This is why it’s crucial to use norm charts as one piece in assessing a child.

The “age of acquisition data are not enough for clinical decision making or to determine eligibility for services…consider children’s speech production, perception, comprehensive independent and relational analysis, intelligibility, stimulability, phonological awareness, spelling, reading, academic and social impact, as well as insights from children and significant others in their lives.” (Crowe & McLeod, 2020)

What’s the difference between an average and a milestone?

An average is what 50% of children can do at a specific age. A milestone is what 90% of children can do at a specific age.

When reading research and looking at norm charts, be sure to find the criterion for the data represented. People may interpret milestones as averages, which can be misleading when examining a child’s development.

Is “the late eight” still evidence-based?

It’s now “early 13” (ages 2;0-3;11), “middle 7” (age 4;0-4;11), and “late 4” (ages 5;0-6;11).

Early 13: /b, n, m, p, h, w, d, ɡ, k, f, t, ŋ, j/
Middle 7: /v, ʤ, s, ʧ, l, ʃ, z/
Late 4: /ɹ, ð, ʒ, θ/

(Crowe & McLeod, 2020)

What’s the difference between a delay and a disorder?

A language delay is when a child’s language skills develop in the pattern we expect, but not at the same rate as their peers. A language disorder is when a child is not following the typical pattern of development. For example, they may be skipping certain steps.

What counts as a word when looking at vocabulary norms?

A word is anything that is consistently produced and holds the same meaning. These can be word approximations, animal sounds, or sound effects. Phrases such as “all done,” “thank you,” and “night-night” are considered one word. They are learned as one chunk and hold one meaning.

Are articulation norms different depending on gender?

No, the differences are slight and only a matter of months apart.

Free Speech Development Norm Chart Cheat Sheets

Download the Free Development Cheat Sheets

This download contains three pages: a speech sounds development cheat sheet, a language development cheat sheet, and an elicitation scene.


  • speech sound milestones
  • phonology ages of elimination
  • vocabulary averages
  • morphology stages
  • find & say picture scene

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