Developmental Language Disorder & Dyslexia

Carlin Graveline Ku discusses developmental language disorder, and shares how language skills and reading skills intersect. Carlin explains why DLD is hard to identify, and the importance of understanding the root cause of difficulties in reading. 

Read Untangling DLD and Dyslexia 

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Lauren Clouser:

Welcome to the LDA Podcast, a series by the Learning Disabilities Association of America. Our podcast is dedicated to exploring topics of interest to educators, individuals with learning disabilities, parents, and professionals to work towards our goal of creating a more equitable world. Hi everyone. Welcome to the LDA Podcast. I'm here today with Carlin Graveline Ku, a subject matter expert and content developer for the AIMs team. Carlin, thank you so much for being here.

Carlin Graveline Ku:

Thank you for having me.

Lauren Clouser:

Of course. We're so excited today to talk about developmental language disorder. But first, could you tell us a bit about your background?

Carlin Graveline Ku:

Sure. So I am actually a speech language pathologist by training, so I've done a lot throughout my career, but the past several years, while I was still practicing, I was primarily focused on treating language and literacy-based disorders. So this topic for today is really near and dear to my heart. So I appreciate you having me. 

Lauren Clouser:

Absolutely. And we'll definitely link to your recent article in our show notes so people can take a look. It's a fantastic article that really dives into developmental language disorder. So what is developmental language disorder, and how does it impact students?

Carlin Graveline Ku:

Sure. So developmental language disorder, or it's known by, you know, just simply DLD, is one of the most common neurodevelopmental conditions that we have. So when we use that term, neurodevelopmental, we mean that these are language difficulties that are persistent through someone's life, not necessarily to the same degree, but that they had these language challenges from early childhood when they were beginning to speak. So it's really important to note that that doesn't necessarily mean that we identified them as having a language disorder or even a delay at that time, but that they didn't have typical communication and language patterns and then have some sort of traumatic event like a stroke or a traumatic car accident that caused these language difficulties. So DLD is also considered a persistent disorder. So it's not temporary. So sometimes we think about language delays for those very young children, toddlers who maybe aren't speaking and meeting all their communication milestones when they're two years of age, but then they catch up.

And so this doesn't necessarily apply to them, but just kind of those continued struggles. So DLD can impact both comprehension, their understanding and or use of spoken language, and that can really incorporate any of those language domains, be it phonology, semantics, syntax, morphology, pragmatics. And while it doesn't necessarily impact all of those domains, it usually does impact more than one domain. It's not usually isolated to just one of those domain areas, with maybe an exception there being pragmatics. But when we think about how it impacts students, that can be really, really variable. For young children, that might be those grammatical mistakes, you know, difficulty with word endings. You're over generalizing that past tense verb ending and you're saying swimmed and she goed there instead of she went there. So it might be like errors like that.

But we don't typically see a lot of those errors once we get into upper elementary grades and beyond. So a lot of times this looks like simplistic use of language. So overusing really vague terms, you know, ‘that thing,’ ‘that stuff.’ Difficulty thinking of the right word to say. So it's: oh, what's that called again? What's that thing? Using really simple language. So over relying on words like: “sad,” “big,” rather than more sophisticated or specific terms, using shorter sentence structures or shorter sentences and more simpler sentence structures. So of course this can impact students in the classroom in terms of how they're understanding more academic language, how they're understanding their reading and their writing.

Also, we do see that sometimes this impacts children with DLD more globally through their academics too. Like they're much more likely to have difficulty with math, for example, because instruction and math can still be very language heavy.

Lauren Clouser:

I appreciate you putting out that it's not just language arts where we would see it, but it can impact lots of other areas as well. And so to build off of that, it seems like there's some similarities with DLD and dyslexia, but also some differences. So would you be able to break that down a little bit further for us?

Carlin Graveline Ku:

Yeah, absolutely. And I'm glad you bring that up because DLD and dyslexia are both language based disorders. And I think that with more people talking about DLD, and especially with the new definition of dyslexia that IDA put out in the fall, and just including more language in that definition, I think that there's some confusion there. And there's just confusion because there can be potentially so much overlap between these, even though they are kind of distinct disorders. So we can think of DLD as being that kind of language-based area of difficulty, and it can impact reading, whereas dyslexia is kind of the reverse of that in some ways. Where dyslexia primarily is a difficulty with word based reading. And it almost always involves that kind of phonological difficulty, and you can have other language-based weaknesses there.

Lauren Clouser:

And so it's also possible for DLD and dyslexia to occur, right?

Carlin Graveline Ku:

Absolutely. And they really, really frequently do. It's really hard to put a number on that because research methodologies just vary so much. And so you think about it in terms of, if I'm doing a research study and I want to see how many students with dyslexia have DLD, if I conduct that study by looking at all of my students and going through their academic records and asking their parents do they have DLD, that's going to give me a very different number of prevalence than if I take all those students with dyslexia and then give them language assessments, and see if they meet diagnostic criteria for DLD. And why those give us so different numbers is because DLD is so significantly under-diagnosed. But because of that, when you look at research, you see really kind of varying percentages for that co-occurrence between DLD. But you know, sometimes it's as high as 50% either way, that 50% of kids with DLD have dyslexia and 50% of kids with dyslexia have DLD.

And it's really important to note too, because I think the misperception is that children with dyslexia tend to be strong in their language. I hear that sometimes where, oh, kids with dyslexia, as soon as you read it out loud to them, they understand perfectly. And they might understand, they probably understand better than if they aren't able to access that text by reading it. But it doesn't necessarily mean that they're understanding that text perfectly, because we do find that kids with dyslexia, even if they don't meet diagnostic criteria for having DLD, they do tend to have relatively weak language skills. And so they're still often having those language weaknesses that might be kind of low average, or right below that kind of range of average, even if they aren't diagnosed with that actual language disorder.

Lauren Clouser:

Okay, and you had mentioned that DLD is under-identified. Why is that?

Carlin Graveline Ku:

Oh, a lot of reasons, unfortunately. I wish it was just one reason so we could just point to it and fix this. But I think there's several different causes that are contributing to it. One is, like I mentioned, it's not a matter of just errors that they're making. Sometimes those errors can be easier to pick up. That's why we don't have as much under-identification of children with speech disorders. For example, if they're trying to say the word red but they're saying wed, that's easier for me to pick up on and identify. But when we're saying that these students are primarily just using simple language and unsophisticated vocabulary, and saying ‘thing’ and ‘stuff,’ well, we all do that, and all children do that.

And so it's not easy to pick up on. When is that kind of simple language and unsophisticated vocabulary done to too much of a degree? So teachers, one, they're not trained in identifying DLD, and two, it just is easier to be masked in everyday kind of conversation. Everyday oral language also tends to just be really simple in general, when we're speaking to each other, even college educated adult to college educated adult, we tend to use relatively simple vocabulary, relatively simple sentence structures. And you know, there's been some interesting research that says that how we use language conversationally tends to be much simpler than the written language, or the language when it's written down, even when it's for children, like we would see in children's books. And so it's easier for students to get by in that oral language because there is just less of an expectation for anyone to use rich and sophisticated language, or for them to understand rich and sophisticated language, because we tend to be speaking, using simpler words and language to them. So yeah, there's just those several reasons. And we can also consider that children are sometimes pretty good compensators.

So if the teacher is giving what might be a complex direction, but all of the other children in his class are standing up and putting one hand on their head, they're probably going to follow along and do the same thing, even if they didn't necessarily understand all of that direction themselves. We can also think about how oral language isn't just simple relative to written language, but that it is usually pretty redundant. Also, when we are speaking, we aren't just using words, we're using our vocal inflection, we're using our facial expressions, we're using gestures. Teachers and presenters are often really good about highlighting those really key points to help everyone else understand the big takeaway. Also, we're changing the rate of our speech. We might pause before we say something really important. We might be raising our eyebrows.

You know, we're putting more emphasis on those specific words. So we're giving a lot of help. We're giving a lot of those scaffolds without even thinking about it, to help our audience understand. And so for those reasons, that's very helpful for these children with language difficulties to be able to compensate. But that's also one of the reasons why they can hide a little bit.

Lauren Clouser:

That makes a lot of sense. I wanted to talk a little bit about how a DLD diagnosis intersects with the IDEA speech and language impairment.

Carlin Graveline Ku:

Sure. So I think that this is a really confusing point for a lot of people. And, you know, I hear all the time that people either consider DLD new or confusing. And it's really not, you know, the L in language is that L in speech language pathology. Having a language disorder isn't anything that's new. There's just a lot of confusion over terminology.

And so one of the reasons for that, and there are several, but one of the reasons for that is that when you are immersed in a school system, you're not necessarily thinking about or using diagnoses in the same way that school psychologists, or rather licensed educational psychologists or speech language pathologists who are working in a private practice might be. So within a school system, we are looking at Ed Code under IDEA. And so we're not looking at diagnostic labels like DLD or dyslexia. We're looking at eligibility categories like SLI, that speech or language impairment, or SLD. And so while a student who either has DLD or may qualify as having DLD most likely falls under the umbrella of that eligibility requirement of speech or language impairment, they do differ a little bit just in terms of where that cutoff is. And so it is possible that you meet diagnostic criteria for DLD, but you don't meet eligibility criteria for speech and language impairment in a school system.

Lauren Clouser:

Gotcha. And so could you expand a bit on how that impacts how students with DLD are served in public schools?

Carlin Graveline Ku:

Yeah, they're under-identified and underserved in public schools. And really significantly also, I've heard estimates that we're only serving 20% of children who have language disorders in a public school. Those percentages aren't new. They've actually been persistent for decades, and they're not tracking any better in recent years, which is really, really unfortunate. So a lot of that does have to do with that under-identification, because we're not finding these children that have language disorders. Often when we find the children with language disorders, it's not even necessarily the ones who are impacted the most severely. Usually it's because they have other things like behavior difficulties or executive functioning challenges, or articulation difficulties on top of those language impacts.

Oftentimes too, when teachers are identifying that there is a problem, it's that they're identifying that that student is struggling with reading comprehension. Because we talked about how written language tends to be much more sophisticated and complex than oral language. That can be when children's language difficulties really come to the table much more evidently. But what often happens, not always, but what often happens is these students might get referred for an assessment based on their challenges with reading comprehension. And that school psychologist may or may not say, oh, I wonder if the root problem of their reading comprehension difficulties is language. And I wonder if I should rope in the language expert in the building, the speech language pathologist, to be a part of this assessment. These children might be somewhere in the system, but they're not necessarily being assessed for an SLI,

that speech or language impairment assessed by a speech language pathologist or receiving language intervention by that SLP.

Lauren Clouser:

Well, and if we are able to identify DLD, what are the types of intervention and support that they should be receiving?

Carlin Graveline Ku:

Similar to intervention for reading challenges or other learning disabilities, it really necessitates interventionists to be able to look specifically at where those challenges are. So just like if I say, oh, I have a child with reading difficulties, that doesn't tell me how to help them. I don't know if I need to work on phonics and phonological awareness... I'm sorry, phonics and phonemic awareness. Or if I need to work on fluency or reading comprehension. Knowing that a student has language challenges also doesn't give me specific enough information to help.

And so that's why that assessment from an SLP can give us a more in-depth look at those children's language profile so we can give more targeted intervention into their vocabulary, into their syntax and morphology, or more kind of discourse-level skills that they might need targeting on or targeted intervention with. But intervention there is explicit and it tends to have a lot of repetition and depth involved. So for example, if I'm giving vocabulary instruction, I know that one of those characteristics of children with Developmental Language Disorder is that they need a lot more repetition and to be able to learn new words. It's harder for them to learn new vocabulary. Not only am I repeating this practice multiple times, but I'm also providing a lot more depth and a lot more context around that word. I'm not simply providing them a definition and then expecting them to memorize that. That wouldn't necessarily be helpful for these kiddos.

And we also know, too, that we would want to integrate both oral language and reading with that language intervention as well.

Lauren Clouser:

Could you expand a little bit more about why we need to know these things to have an effective intervention about where the student is impacted?

Carlin Graveline Ku:

It's not necessarily super important to me when I'm working with a student to focus solely on the diagnosis. What's more important to me is knowing the root of those difficulties. So I'm actually going to give an example here. And all the stories that I tell here are real. So I was working with a little girl once, and she was reading the word matches. So M -A-T-C-H-E-S. And so it was provided to her in isolation. So there was no context of a sentence around it. She decoded it correctly and said, matches. And I said, yeah, that's great. Use that word in a sentence for me. And she said, I sleep on a matches on my bed.

All right, so when we're looking at that, right. That tells me a lot of really interesting information about what she's processing and how. So, one, I see the phonological. Really significant phonological difficulty there that she isn't discriminating between the word matches and mattress. Those sound similar enough to her that she's kind of considering them the same word. This is also telling me that she didn't have that layer of morphological knowledge kick in and say, oh, wait, but that word has an es at the end. And so it should be either the verb ending suffix or that plural marker. And mattress has neither of those as a singular noun. And it's also telling me something about her vocabulary that she didn't immediately recognize that word matches. And so these are all just kind of mingled together, and these different domains of language play off of each other. They intersect with each other. She happens to have both dyslexia and developmental language disorder.

But the diagnosis of what was impacting that decision didn't necessarily matter. Both DLD and dyslexia can have those significant phonological impacts. And so if she only had one diagnosis, I'm still kind of responding in the same way to the phonological challenge rather than the disorder. And so to bring me back for me, similar to knowing that you have a language difficulty, knowing that you have a reading difficulty, that doesn't tell me enough to plan targeted intervention. And knowing a disorder helps. Knowing that you have dyslexia, knowing that you have DLD, that helps narrow it down some. But again, I still need further, more detailed information from there to know specifically how to help that student. Because not every student with dyslexia needs the same course of treatment. And not every student with DLD is going to benefit from the same intervention either.

Lauren Clouser:

Absolutely. And then before I let you go, I just have one more question. If you could change anything about the policy and practice around DLD, what would be the things that you would implement?

Carlin Graveline Ku:

We absolutely unequivocally need to be screening for DLD. We're doing more with universal screeners for reading difficulties, which is fantastic and so important and necessary. But those universal screeners really need to also include that risk for language disorders as well. So whether those are happening at the pediatrician's office or in schools, ideally both. I think that is just my number one in terms of what needs to change to help ensure that we are identifying more of these students and helping them get the intervention that they need. Kind of secondary on my wish list would be just continuing to raise awareness for DLD and training for teachers so they know a little bit more of what they are looking for. This certainly isn't secondary at all, but really just advocacy in the field of speech language pathology.

Because another impact that I didn't really get into was that we are really short staffed with SLPs across the country. There's lots of schools who don't have an SLP. They're not in the building or they don't have enough. And those SLPs often have just huge out of control caseloads, really in terms of just advocacy and better working conditions for our SLPs so that these professionals have the time and space and ability to really help those students once we are able to catch them more.

Lauren Clouser:

Absolutely. Carlin, thank you so much for being on today. This is such a great discussion about the breakdown of developmental language disorder.

Carlin Graveline Ku:

Thank you so much for having me. I loved being here.

Lauren Clouser:

Thank you for listening to the LDA podcast. To learn more about LDA and to get valuable resources and support, visit LDAAmerica.org.