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New research shows English, and nonnative Korean and Mandarin readers comprehend more with Cascade!

by Jack Dempsey, Director of Research

A Report on Recent Research

Following evidence that the Cascade Format helps elementary students better comprehend texts (Van Dyke & Dempsey, submitted), Dr. Julie Van Dyke, Chief Scientist at Cascade Reading, and I teamed up with Dr. Kiel Christianson, Professor and Chair of Educational Psychology at the University of Illinois, to test how readers with different language backgrounds benefited from this text format.

The central finding is that both native and nonnative readers of English enjoy a comprehension benefit when reading in Cascade after only 30-60 minutes of reading.

In fact, the comprehension advantage in Cascade versus traditional text formatting for first-language Korean and first-language Mandarin English language learners (ELLs) was numerically larger than the significant advantage experienced by native speakers of English (English > 2%, Korean > 5%, Mandarin > 11%). Read more about the study below!

Why is this Research Important?

According to the Nation’s Report Card, 12th grade ELLs consistently score significantly lower than their native English learner (EL1) counterparts (see Figure 1), and it remains unknown how the pandemic has changed these numbers. Although there are quite a few reasons for this gap, such as differences in vocabulary knowledge (1) or listening comprehension ability (2), some studies suggest that syntactic awareness may be particularly important for predicting ELL reading comprehension success in elementary grades (3,4,5) and beyond.

One explanation for syntax’s vital role in ELL reading comprehension outcomes is dubbed the “Shallow Structure Hypothesis,” (6,7,8,9) put forth by Drs. Harald Clahsen and Claudia Felser at the University of Potsdam in Germany, experts in the fields of second language acquisition and psycholinguistics.

Their work, based on decades of research, makes a compelling argument that ELLs rely less on grammar when reading compared with EL1 readers, focusing instead on different meaning-based cues to comprehension. Therefore, using the structure of language to comprehend texts, something EL1s have an easier time doing, might be less accessible for ELLs. 

That’s where Cascade Reading comes in. Since the Cascade Format makes the structure of the language more readily accessible, it may help ELLs take advantage of the language’s grammar while reading, leading to better comprehension.

Graphs showing 12th grade English Language Learners consistently score significantly lower than their native English learner counterparts

Figure 1. Trend in twelfth- grade NAEP reading-achievement level results, by status as English learners

Graphs generated directly from These data are reported from 2019, which is the most current reported year for this age group by the Nation’s Report Card.

Overview of our Research Study

We recruited 90 participants from the University of Illinois community, mostly students, who grew up either speaking English, speaking Korean and not English, or speaking Mandarin and not English. From each language group, half of the participants were randomly chosen to read in the Cascade Format while the other half read in the traditional format. Regardless of format, all participants read the same six academic passages, broken into two separate reading sessions, provided with permission by

After reading each passage, they were asked fourteen comprehension questions that targeted their understanding of relations within the text (e.g., who did what to whom) in addition to questions about main ideas. Participants also completed tasks revealing their word-level decoding ability, oral reading fluency, and reading comprehension in English to help us properly control for other reading-related abilities in our statistical models.

Findings - Comprehension Improves with Cascade

Using state-of-the-art statistical modeling techniques (Bayesian hierarchical models), controlling for factors such as initial reading ability, word-level decoding, and oral reading fluency, we found an overall advantage for participants reading in Cascade. Regardless of language background, participants who read in the Cascade Format performed significantly better on the comprehension questions following the passages. 

Using model-based estimates, we found that, after just one single session of reading in Cascade, comprehension during the second reading session was better relative to that of participants reading in the traditional text format (English = 2.6% advantage, Korean = 5.3%, Mandarin = 11.1%). Figure 2 below shows this Cascade advantage across language groups.  


ESL Research Results - English, non-native Korean and Chinese showing significant comprehension improvement when reading in Cascade Format

Figure 2. Average performance on comprehension questions across language groups and text formats


Conclusions and Future Directions

The conclusion from this study is clear:  Korean and Mandarin ELLs, in addition to individuals who have English as their first language, comprehended more when reading in Cascade compared to similar individuals reading in traditional text formatting. Both ELL groups seem to enjoy larger benefits than those who grew up speaking English, and this may be due to the fact that our participants were college students, and therefore already quite proficient in reading comprehension.  

However, even though they were quite advanced, Cascade helped – demonstrating that Cascade Reading isn’t just relevant for elementary age learners.

Not only are these results promising for improving reading comprehension in the US, but there are also millions of ELLs abroad that could benefit from the Cascade Reading Format. The next obvious step would be to look at other language groups; for example, we are currently recruiting Spanish speakers for a similar study, which is particularly important in the US ESL educational context. 

There is also great promise that Cascade could help ELLs as they are beginning to learn the language in addition to those who already have a working proficiency in English. That is, Cascade Reading could help people read in a new language and could also help them learn a new language, especially when that language’s grammar differs from that of their first language(s).

A solution to improving reading comprehension cannot help just a small section of the population – there is room for growth everywhere. At Cascade Reading, one of our core research principles is to ensure that the tools we create help a wide variety of readers from different backgrounds. 

We look forward to sharing more findings as we continue to research how Cascade can change reading, thereby changing lives. If English is not your first language, or even if it is, please try it out and let us know your thoughts!


Dr. Jack Dempsey

Director of Research, Cascade Reading

1) Droop, M., & Verhoeven, L. (2003). Language proficiency and reading ability in first‐and second‐language learners. Reading Research Quarterly, 38(1), 78-103.
2) Li, L., Zhu, D., & Wu, X. (2021). The effects of vocabulary breadth and depth on reading comprehension in middle childhood: The mediator role of listening comprehension. Reading & Writing Quarterly, 37(4), 336-347.
3) Farnia, F., & Geva, E. (2013). Growth and predictors of change in English language learners’ reading comprehension. Journal of Research in Reading, 36(4), 389-421.
4) Shiotsu, T., & Weir, C. J. (2007). The relative significance of syntactic knowledge and vocabulary breadth in the prediction of reading comprehension test performance. Language Testing, 24(1), 99-128.
5) Zarei, A. A., & Neya, S. S. (2014). The effect of vocabulary, syntax, and discourse-oriented activities on short and long-term L2 reading comprehension. International Journal of Language & Linguistics, 1(1), 29-39.
6) Clahsen, H., & Felser, C. (2006). Grammatical processing in language learners. Applied Psycholinguistics, 27(1), 3-42.
7) Clahsen, H., & Felser, C. (2006). Continuity and shallow structures in language processing. Applied Psycholinguistics, 27(1), 107-126.
8) Clahsen, H., & Felser, C. (2006). How native-like is non-native language processing?. Trends in Cognitive Sciences, 10(12), 564-570.
9) Clahsen, H., & Felser, C. (2018). Some notes on the shallow structure hypothesis. Studies in Second Language Acquisition, 40(3), 693-706.
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