What teachers need to know about sentence comprehension

When working towards developing students’ reading comprehension, sentences matter – but they are often neglected in favour of other areas of focus such as vocabulary.

By Tim Shanahan

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A while back, I posted an opinion piece calling for the explicit teaching of sentence comprehension. With schools aiming to expose kids to complex text, such instruction would be de rigueur. Texts are often complex because they include complicated sentences, and experience tells me that students often fail to grasp the meaning of individual sentences – undermining their ability to identify main ideas, make inferences, draw conclusions or answer any of the other question types.

Given that comprehension lessons tend to focus on ‘prior knowledge’, vocabulary, text reading with follow-up questions and comprehension strategies, the lowly sentence gets short shrift in most programs and classrooms.

In any event, while that rant gathered some attention, it came up short. Accordingly, I have decided to take a mulligan.
That blog articulated my opinions, but neither marshalled the research evidence nor provided much in the way of helpful instructional guidance. It called for action but was terse on specifics.

This piece should remedy those omissions.

To tell the truth, when I wrote that article, I didn’t bother to search for research on sentence comprehension because that topic never attracted much attention. There were some old studies indicating that teaching formal grammar had no impact on comprehension or writing. That seemed to settle it for most of us.

When I was working on my doctorate, a prominent reading scholar told me that “Noam Chomsky is dead”. He meant it figuratively as he was trying to dissuade me from squandering my time on something as pointless as sentence comprehension.

No matter my excuses, boy was that a foolish oversight!

Over the past two decades – slowly, gradually – research on syntax and reading comprehension has accumulated. And, over the past couple of years, the numerous publications appearing in high-quality psychological, educational and linguistic journals suggest that being a sentence-comprehension researcher is now a respectable line of work, along with social media consultant or TikTok dancer.

First, the research.

These days, we’re all doing some handwringing over supply lines. Nevertheless, there are clearly no supply line problems to report when it comes to sentence-comprehension studies. The desert has become an oasis. There is now a slew of rigorous studies revealing that an understanding of syntax is correlated with reading comprehension (Rand, 2002). That simply means that students who know more about how sentences are constructed do better on reading comprehension measures.

Even more persuasive is that many such studies examined that relationship AFTER controlling
for differences in decoding ability, vocabulary knowledge, memory and/or other relevant reading skills (Bowey, 1986; Bowey & Patel, 1988; Brimo et al., 2017; Brimo et al., 2018; Cain, 2007; Catts et
al., 2006; Cutting & Scarborough, 2006; Deacon & Kieffer, 2018; Gaux & Gombert, 1999; Farnia & Geva, 2013; Goodwin et al., 2022; Gottardo et al., 2018; Hagtvet, 2003; Mackay, et al., 2021; Mokhtri & Thompson, 2006; Nation & Snowling, 2000; Nippold, 2017; Nomvete & Easterbrooks, 2019; Poulsen et al., 2022; Scarborough, 1990; Scott, 2015; Shiotsu & Weir, 2007; Sorenson Duncan et al., 2021; Tong & McBride, 2015).

In other words, if all students did equally well on decoding, vocabulary and memory tests, we’d still see variations in reading comprehension ability because of syntax difference. The kids who understand syntax comprehend better than the ones who don’t.

That list of studies is impressive, but not comprehensive. I didn’t search carefully for these studies – combing through reference lists, using a variety of search terms and strategies, considering books and doctoral dissertations, and so on.

It is fair to point out that some such studies didn’t find significant relationships between syntax and comprehension (e.g. Cain & Oakhill, 2006), though the data are sufficiently one-sided enough to conclude that any honest meta-analysis would report that knowledge of syntax is an essential reading skill.

That collection of studies cited above found sentence knowledge to be important to comprehension as early as 30 months old and throughout the school grades K–12. They found that syntax mattered with regular classroom kids and those with dyslexia. They reported this pattern in English, French, Dutch and Cantonese. They found syntax to matter with native English speakers and with English Language Learners. Syntax played a significant role in comprehension both in studies that measured those simultaneously, and in longitudinal studies which considered the role of the relationship in learning and development.

The amount of comprehension variance explained by syntax varied quite a bit from study to study (~5% to 30%). Researchers attributed some of those differences to the nature of the syntax measures, suggesting that the ability to make sense of complex sentences is more crucial than the ability to evaluate grammatical accuracy (e.g. Brimo et al., 2018). Researchers paid less attention to variations in reading comprehension measurement.

The texts included in comprehension tests can vary a great deal in sentence complexity, and in whether the questions they ask tap into this complexity (Shanahan & Kamil, 1984).

This concern is important since syntax is a particularly important factor determining text complexity or comprehensibility (Graisser, et al., 2011; Stenner & Swartz, 2012). Texts with more complicated sentence structures will be a special challenge for kids who lag in sentence comprehension ability. However, at least for fifth graders, the ability to make sense of sentences with simple structures was more closely related to reading comprehension than doing so with more difficult sentences; though this may have been due to the specific demands of the particular comprehension measure used in the study (Sorenson Duncan et al., 2021).

Another relevant collection of studies is those focused on oral reading fluency or text reading fluency. Such research has long shown that oral sentence reading requires skills beyond those required to read word lists – even when the words in the lists and sentences are identical (Jenkins et al., 2003). That study found sentence reading to be more predictive of reading comprehension than was word

list reading. Students with specific reading comprehension deficits read word lists as well as comparison students, but perform more poorly than controls on text reading fluency (Cutting et al., 2009). Research also has reported that syntax and text prosody are related to each other and to reading comprehension (Veenendaal et al., 2015).

If that provocative but incompletereview of the research isn’t enough to convince you that sentence comprehension is a thing, then you likely can’t be convinced. Your lifetime membership in the Flat Earth Society is safe and secure for the time being.

For those of you who are more open minded, let’s turn to what we know about teaching sentence comprehension.

I’d love to present an equally impressive array of studies showing that if you teach sentences your state test scores will reach levels just this side of Nirvana. Unfortunately, I can’t do that.

A thoughtful review (MacKay et al., 2021; Stoddard et al., 1993) recently concluded that this research is so severely limited and insufficient that it would be unwise yet to proceed pedagogically. The reasoning of these researchers is admirable and consistent with what I usually espouse – don’t try to apply basic research to classroom practice. Wait for the instructional studies!

MacKay and company rightly point out that some interventions aimed at improving sentence comprehension haven’t worked (e.g. Balthazar & Scott, 2018), and that interventions aimed at sentence comprehension have been hopelessly confounded (e.g. Morris, et al., 2012; Proctor, et al., 2000; Reynolds, 2021). Although these studies reported significant reading comprehension improvement, they didn’t focus on syntactic work alone but also taught morphology, vocabulary or text structure; perhaps the gains were due to one or another of them.

This article originally appeared on the author’s blog, Shanahan on Literacy.

This article appeared in the Sept 2025 edition of Nomanis.