Parent input predicts toddlers’ vocabulary development

This longitudinal study of 50 families and their typically-developing children examined how parent input effects child vocabulary scores one year later. Controlling for factors like the child’s prior vocabulary skill, quantity of input, and SES, they found that:

  • At age 1 ½, quantity of parent input most predicted later vocabulary.

    Note this doesn’t mean other things they didn’t measure couldn’t also impact it, like joint attention or parental responsivity

  • At age 2 ½, diversity of vocabulary in the input most predicted later vocabulary, even when controlling for input.

    Also, other research on children this age has found that vocabulary grows best when directed to the child, not via ambient conversation.

  • At age 3 ½, language complexity matters most

    e.g. decontextualized language like narratives, and explanations (such as answering “Why?” questions fully) 

And for an Early Intervention SLP, this all seems pretty logical. But transforming it into a simplified version for coaching parents could also be quite useful, such as saying:

  • For babies and one-year-olds, talk to your child, and focus on amount.

  • For two-year-olds, talk to your child, and focus on words.

  • For three-year-olds, talk to your child, and focus on sentences and stories.

… and then coaching what this would look like, specifically. Then, of course, the question becomes—would this be adequate, and would it make a difference? We don’t know. The next review (actually, the next two!) show research that digs in deeper to what’s needed for success.


Rowe, M.L. (2019). A longitudinal investigation of the role of quantity and quality of child-directed speech in vocabulary development. Child Development. doi: 10.1111/j.1467-8624.2012 

Throwback (2017): Not just more talk, but Toy Talk

We know that the language input children receive matters. But telling parents to “talk more” might not cut it, especially as you approach the twos and threes! So how can we instead make sure the input supports the child’s grammatical growth?

Consider Toy Talk. It’s a strategy parents are taught to use (in this study, via three parent coaching sessions right before the child’s second birthday), where they’re told to respond to the child’s interests in play, and importantly:

“Talk about the toys” and “Give the object its name” 

Simple, huh? But the effects are substantial. It will basically: force adults’ use of nouns instead of pronouns in the subject position, which pulls the subject and verb away from one another, rather than allowing contractions that may be learned by the child as one unit instead of two morphemes. So it looks like this:

Without toy talk:

It’s soft.

He’s running. 

With toy talk:

The kitten is soft.

The horse is running.

It also makes learning verb tense and agreement easier by forcing marking and helping kids notice these morphemes in the parents’ input:

Without toy talk:

Hop onto the horse.

Drink some water. 

With toy talk:

The cowboy hops onto the horse.

The horse drinks water. 

Toy Talk has been found to be fairly easy for adults to learn and use, and improves the growth trajectories of the children’s unique combinations of subjects and verbs and tense-agreement morphemes.

We don’t yet know how big of an impact strategies like this could make for kids with DLD, but so far it looks promising, and certainly worth trying! Learn more, and grab a parent-friendly handout here.


Hadley, P.A., Rispoli, M., Holt, J.K. (2017). Input Subject Diversity Accelerates the Growth of Tense and Agreement: Indirect Benefits From a Parent-Implemented Intervention. Journal of Speech, Language, and Hearing Research. doi: 10.1044/2017_JSLHR-L-17-0008

Hadley, P.A., Rispoli, M., Holt, J.K., Papastratakos, T., Hsu, N., Kubalanza, M., McKenna, M.M. (2017). Input Subject Diversity Enhances Early Grammatical Growth: Evidence from a Parent-Implemented Intervention. Language Learning and Development. doi: 10.1080/15475441.2016.1193020.

Let’s hear it for the verbs! Parents’ early verb use predicts children with ASD’s later verb vocabulary


Verbs are important for early language development; they are the building blocks for early sentences and help kids tell us about the things that are happening around them. But as we know, many of our children with ASD struggle to learn and use them flexibly. We know from the literature that for typically developing children, parents’ verb use can predict their later verb vocabulary. These researchers wanted to know if the same was true for children with ASD.

To do this, they measured the verbs that parents of children with ASD used during “follow-in utterances.” Follow-in utterances are comments that parents make during moments when they and their child are both focused on the same thing. So if a child knocked down a tower of blocks and looked up at his mom, her saying, “The tower crashed!” would be a follow-in utterance. The researchers looked at three aspects of parent verb use during follow-in utterances:

  1. The quantity of verb input, i.e., how often parents said verbs

  2. The diversity of verb input, i.e. how many different verbs parents said

  3. The grammatical informativeness of verb input, i.e. how much rich morphological information surrounded the verb. For example, “We’re jumping” would be more grammatically informative than “jump.” (See the article’s appendix for additional definitions and examples.)

They found that together, these three aspects of parent verb use during follow-in utterances predicted children with ASD’s later verb vocabulary. Because this is a correlational study (and doesn’t tell us what causes what), we’ll need further research to tell us if teaching parents to increase their quantity and quality of verb use will improve their children’s verb vocabulary. That being said, here are some ways authors describe that this line of research may impact what we teach parents:

  • We could teach parents to expand what their child says by adding a verb. For example, if the child says, “baby,” we could teach the parent to respond with, “the baby is sleeping,” rather than adding on to the noun phrase (e.g. “little baby”).

  • We could encourage parents to use diverse verbs during follow-in utterances, rather than over-relying on a small number of verbs and verb forms (such as “I want _____,” or “I need ______”).

  • We could teach parents to use grammatical language, rather than telegraphic. Because including grammatical morphemes seems to support children’s learning of verbs, we could teach parents to model fully grammatical language. For more research about using grammatical vs telegraphic language, see our previous review here.


Crandall, M.C., McDaniel, J., Watson, L.R., Yoder, P.J. (2019). The relation between early parent verb input and later expressive verb vocabulary in children with autism spectrum disorder. Journal of Speech, Language, and Hearing Research. doi:10.1044/2019_JSLHR-L-18-0081.

Clinical Tutorial Throwback (2018): How to measure syntax in early intervention (hint: MLU alone won’t cut it)

"Describing sentences in terms of utterance length may be appropriate for communicating expectations with non- language specialists, but we believe it is crucial for speech–language pathologists to differentiate word combinations from sentences in order to recognize early difficulty with the acquisition of sentence structure…and to develop intervention plans to facilitate grammar for children with or at-risk for language disorders." 

(Hadley et al., 2018)

Picture it: You’re an EI therapist, and you’ve recently evaluated two two-year-olds. In addition to a standardized assessment, you also collected a language sample to evaluate their expressive language skills. Here’s a sample utterance produced by each child:

Child 1:  I see you!

Child 2:  Dog run.

At first glance, it seems logical to assume that Child 1 has more advanced language skills, right? He or she is producing 3 word utterances, while Child 2 is only producing two. And, utterance length is something that we as SLPs should be looking at when we evaluate young children’s language development. But, focusing only on utterance length will most likely result in an overestimation of a child’s language abilitiesThis recent article serves as a good reminder that we should be extending our language analysis beyond utterance length to include syntax. And, the best part is, the authors explain a quick and easy way to analyze grammatical structures in young children, along with developmental expectations that can be used to identify intervention targets.
The method of analysis that the authors recommend is based first on distinguishing between a word combination and a sentence. What’s the difference? Well, we know that the hallmark of age two is 2-word combinations, right? These are utterances that have an MLU of between 1.5 and 2. Shortly after toddlers begin producing these word combinations, they begin to produce true sentences which include Subject-Verb-Object (SVO) (“I want that.”) and Subject-Verb (SV) constructions (“baby sleep”).
Now, what about “diversity” of those sentences? Sentence diversity has to do with how common or frequently used the words are in a child’s utterance. Put another way, you’re counting the number of different or unique SV combinations that a child produces. So, if we go back to the example of Child 1 and Child 2, the first child’s use of the subject “I” is much more common than the subject “dog”. And, “see you”, although a two-word combination, is most likely a phrase that the child hears and produces often, whereas the verb “run” is most likely less commonly noted in the child’s typical utterances. The authors provide fantastic supplementary materials here that include references and specific procedures for calculating sentence diversity.*
And, while this is all great information, it kinda seems like it’s adding time to the already lengthy process of language sample analysis, right? Well, here’s some good news: the authors provide evidence to suggest that a pared down, quicker version of LSA (what they refer to as, “structure-specific language sampling”) is the way to go if you want to measure sentence diversity. Basically, you’re focusing on and transcribing only one specific grammatical structure within a language sample. And, as an EI therapist, the methods that they recommend for collecting the sample make a lot of sense. For instance, the authors suggest using a parent–child language sample because unstructured conversations provide the most authentic measure of a child’s language skills. (*More information regarding how to collect the sample is included in the supplementary materials.) The best part? As long as you’re consistent with the amount of time that you use to collect the samples, repeated measures of sentence diversity can be used to monitor progress and determine targets for intervention.

All in all, the information in this article seems like it could really be a game-changer for EI therapists who are working with children transitioning from word combinations to more complex utterances. Beyond providing a more specific description of young children’s language skills, this method of analysis may allow SLPs to identify children who will have trouble moving from use of more basic, routine sentence constructions to use of more complex grammatical forms—i.e., kids who may eventually fit the diagnosis of Developmental Language Disorder (DLD).

*The authors are careful to explain that while an assessment of sentence diversity is useful for selecting intervention targets and monitoring progress, a more comprehensive analysis of grammar (such as the Index of Productive Syntax, or IPSN) is needed to identify the severity of a language disorder. One of the 3 supplemental materials included in this article is a table that lists items from the IPSN and how they relate to understanding of sentence structure.

Hadley, P. A., McKenna, M. M., & Rispoli, M. (2018). Sentence diversity in early language development: Recommendations for target selection and progress monitoring. American Journal of Speech-Language Pathology. doi: 10.1044/2017_AJSLP-17-0098.

Perspectives & Tutorials

Sentence diversity in early language development: Recommendations for target selection and progress monitoring

Recall that we don’t review Perspectives, Tutorials, or Opinion pieces. Only empirical research. Technically, these tutorials are lower evidence. But, here’s the tough thing: they’re often very clinically useful, and based upon high-quality empirical research! So what’s an Informed SLP to do?

We’ll tell you when we come across these papers, and if there’s a lot to say, we’ll discuss it on our Evidence Answers page. This article (above) is one such situation. Read more here.

A History of EI/ECSE in the United States: A Personal Perspective

This is a really fantastic perspective on the history of Early Intervention and where we should go next. A must read for anyone making decisions for Early Intervention programs!