There’s a fine art to biting your tongue and walking away and diplomacy is a worthy skill to acquire and hone. Recognizing that we all have differences, is another skill that is fabulous to have. However, sometimes, it’s necessary to find a way to correct a wrong, particularly when it’s a common wrong. (Are you confused yet? Bear with me…please?)
This post has been a while in coming…and I’m fairly sure it will exasperate some and anger others. I sincerely hope that most of you will find it enlightening rather than annoying. I have bit my tongue and walked away from the computer screen a lot lately…now I’m attempting to correct a wrong.I remember being in grad school and learning how to read articulation norm charts. You know, those Iowa-Nebraska norms, or the Sander’s norms (as adapted here). I remember being told that the majority of SLPs read them incorrectly. At that point in time, I remember thinking “yeah, right. It’s not that hard.” However, I didn’t take into consideration the discrepancies among the charts themselves…and, at that time, I didn’t know enough to really apply critical reasoning skills and see if the charts are even measuring the same thing.
Guess what…They don’t. The reason there is so much discrepancy between the charts is because while they all measure sound acquisition, they all have different criteria for what they call “mastery.” Some consider mastery to be at 75% some consider it to be 90%. Some only look at initial sounds, some look at all three positions.
Guess what else…My professor was right. After talking with people on the Facebook SLP pages and on twitter, I’ve come to realize many (maybe not the majority, but definitely a lot) SLPs read these norms incorrectly.
Gregory Lof has a phenomenal handout available called Confusion about Speech Sound Norms and Their Use. I’m going to attempt to explain parts of it here, but I highly recommend you go and read the presentation for yourself. It is fascinating!
Let’s take a look at the Sander’s chart.
As you can see here (hopefully) there is a range for when sounds are considered acquired. Most clinicians that I’ve spoken with believe that the bars indicate the development of the sound, so for instance, with R the child would start to have it at age 3 and it should be fully mastered by age 8. Makes sense, right?
Wrong! What it actually is showing is that 50% of the children age three (3) correctly produce the sound and by age eight (8) 90% of the children have the sound mastered.
Did you catch that? R begins earlier than 8…50% of kids have R at age 3… 3. Hmm. If we wait until 8 to even START to teach how to make the sound, we have put our clients at least 5 years behind the “norm.” Ouch!
Let’s look at what else I see. I often hear that /s/ is a “later developing sound” (I hate that phrase)…It actually has the same bar graph as /r/…so 50% of three-year olds can correctly say /s/. Another common sound that is “later” is “TH.” Voiced TH is developed for 50% of kids at age five, unvoiced by age four.
In fact, if you look at the chart, the majority of sounds are developed by age four. There are two sounds that are a bit later (“th” and “zh”) but that’s it. Two. At least 50% of typically developing 4 year olds have ALL but two sounds correctly produced. hmmm.
Also, another interesting note is that Sanders looked at data from both boys and girls, and included phonemes across words (so initial, medial, and final position). So for those 3 year olds that have /r/? They have them in all positions of the word. (This information can be found here on about page 15.)
Let’s look at the Iowa-Nebraska Norms. This is the norms chart that ND has implemented as their eligibility criteria. It has /r/ as being mastered by 90% of children by age eight (8), while /s/ is mastered by age seven (7). So…let’s see. I often hear that SLPs won’t work on /s/ until after the adult front teeth have emerged, which according to this is after age 7 or 8 because that’s when the central incisors fall out…yet, 90% of typically developing kids have it mastered by age seven (7). Hmm. So if we wait until a child is 8 to start to teach it…well, you can fill in the blank.
Interestingly enough, Smit et al. also found that “reversals” occurred for /b, g, s, z, and l/. Reversals were found when “a predetermined criterion for acquisition is reached by one age group, but not by an older age group.” In other words, even though /s/ was found to be mastered by 90% of children age 7, in reality it was mastered earlier – then enough kids “lost” the skill that they could no longer consider it mastered, and then it re-emerged as mastered at 7. There’s a couple of reasons this could happen; the authors stated perhaps it’s due to “phonologic regression,” or variation in sampling, because the listeners were willing to accept a slightly less precise /s/ for 3-4 year olds than they were for 6 year olds, or perhaps because it is mastered earlier but a slight shift in production occurred and they moved from correct production to error before reverting to an acceptable production again. (Personally, not that I think I’m better than all these famous researchers, I suspect the last is true…they have a good /s/ and then it shifts slightly to an error. This could be due to over emphasis, co-articulation…heck, lost front teeth???) Either way, this research shows that /s/ develops earlier than 7 for the majority of kids.
One fascinating tidbit from Greg Lof’s presentation was the difference between norms. Let’s take a fairly non-controversial sound. We all would expect the sound /p/ to be mastered fairly early. It’s an early developing sound, it’s a bilabial so it’s easily seen and mimicked, it’s unvoiced…easy! We expect toddlers to say “puppy.” Right? Yet, Prather, et al (1975) has /p/ developed at age 2;6. Templin (1957) has /p/ at age 3. Sander (1972) has /p/ at 3. Smit et al. (1990) has /p/ at 3. Goldman-Fristoe (2000) has /p/ at 6;6. (Yes…6;6. That was NOT a typo). The same range can be said for /t/ – anywhere from age 2;6 to age 6;0 depending on which chart you read. For /r/ the range is from 4;6 to 8. Hmm. Some charts have mastery for /r/ at age 4;6? Why do we wait until 4th grade to start to work on it then?
Another fascinating chart to look at is this compilation of the various developmental norms, the year they were done, the number of children who participated, and sample type. If you look, Templin (whose chart is a favorite of many) only had 480 participants and only looked at single-words. Where as Peter Flipsen had 320 participants and used connected speech.
So…where is this all heading? I’d love for you to let me know which developmental norms chart you use. I’d also like to know if your district/state requires you to “wait” for a year after the developmental chart shows the sound should be acquired. More importantly, I’d love for you to consider what you use as guidelines for articulation development. I realize that many of you (myself included) are somewhat limited by our districts/states as to when we can work on certain sounds…Heck, I realize some of you are limited and not allowed to work on articulation at all which is a whole different rant…but, will knowing the differences in norms and how they are often misread make a difference in your therapy? I’d love to hear (even if you disagree with me). Drop me a line in the comments!
Until then….Adventure on!