Say hello to the: Early 13, Middle 7, and Late 4?!
Quick: For those of you who are already caught up on the article that broke the SLP internet, the TL;DR version of this newer article is:
Everyone else, welcome! Let’s go on a journey together. Consider this topic an enchanted forest; the path through may be arduous, but we will all leave with our practices transformed for the better. Is it possible that quarantine at our house is involving a lot of Frozen 2? Perhaps.
Flashback to set the scene: In 2018, McLeod & Crowe published an (award-winning) cross-linguistic review of consonant acquisition. We reviewed it. After that, it blew up online because people saw infographics the authors shared (instead of age-of-acquisition charts looking like this, they looked like this), thought there were totally new age-of-acquisition norms, and grew… concerned about the implications for their caseloads. A lot of the discussion was around the age for mastery of /ɹ/ being a lot younger than we’re used to seeing. Now in fact, this was not “new” data at all, it was a compilation of the existing data in a way that lets us interpret it more correctly. For a full discussion of all this, read this blog post. If you can’t get enough, check out some of the podcasts and articles it links to and you’ll be an expert.
Flash forward to the present day. This intrepid team of researchers is back with another review, summarizing all the consonant acquisition data (15 studies of 18,907 children) specific to US English. So for any skeptics who thought the 2018 results were skewed by encompassing data from multiple countries... sadly no. Actually, a few sounds show up earlier than in the first study. Bid a fond farewell to the Early/Middle/Late 8, and say hello to the new (if less handy to remember):
Early 13: /b, p, n, m, d, h, w, t, k, ɡ, f, ŋ, j/ (Age 2–3)
Middle 7: /v, ʤ, l, ʧ, s, ʃ, z/ (Age 4)
Late 4: /ʒ, ɹ, ð, θ/ (Age 5–6)
Exactly what this means for you depends a lot on how you were using developmental norms to begin with. To the extent that norms do factor into your decision-making, these are the ones you want to be using.
By summarizing data across 15 studies of 18,907 children, this review article presents an updated account of typical consonant acquisition that may seem contradictory to current (entrenched) beliefs in the United States."
But there’s a bigger conversation to be had here. Crowe & McLeod refer us to this (open access) piece from Dr. Holly Storkel that walks through how to use developmental norms appropriately: not in isolation or as an absolute cut-off value, but as one piece of the puzzle. So here’s the hard truth pep talk: If the eligibility criteria you (have to) use are solely based on developmental norms, they are not good criteria. Somebody, maybe you, will need to get this information to the people who make the rules, because chances are they aren’t reading this right now. The Storkel tutorial has a whole section near the end on advocating for change. Reading that, a conversation with co-workers, joining up with your state association… any of these can be the first simple step.
In the meantime, with the next kid who shows up for an evaluation (even if it’s just one kid, for now), consider factors beyond norms to get as full a picture as possible. Crowe & McLeod list out all the considerations you’d ideally be weighing: production, perception, intelligibility, stimulability, phonological awareness, spelling/reading, academic and social impact, and input from the child and important adults (an open-access tutorial for this richer type of assessment is available here). Work within the degrees of freedom you have and flex that clinical judgment!
*Thanks to the @classlab_fsu’s Instagram post for the timely reminder to turn that /r/ upside down! Need more info? Here’s an explanation from Dr. McLeod: “Although ‘r’ is often written as /r/ in English textbooks, the International Phonetic Alphabet uses the symbol /ɹ/ to indicate the alveolar approximant ‘r’ found in English. The consonant /r/ is the trill used in Spanish and many other languages throughout the world.”
Crowe, K., & McLeod, S. (2020). Children's English Consonant Acquisition in the United States: A Review. American Journal of Speech–Language Pathology. https://doi.org/10.1044/2020_AJSLP-19-00168 [open access]
Addendum, December 2020:
If you’re confused on how to square best practice in identifying SSDs with the statutes and guidelines you operate under, this (freely available) article takes all that theory down to the level of your caseload. It discusses all the competing sources of guidance you need to consider when figuring out which kids are going to get services for SSDs in the schools, and which ones carry the most weight (spoiler alert: it’s the law, not best practice). School-based SLPs, this would be a great choice for a journal club or to share at your next speech team meeting.
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