As discussed in our earlier post, reading is the best way to build your vocabulary in a new language. However, reading texts in a foreign language is extremely difficult when you have a limited vocabulary. This results in a Catch 22 — you need a big enough vocabulary to effectively learn new vocabulary words! To get around this problem, people typically resort to a number of sub-optimal and frustrating approaches to reading a foreign language:
- Read simplified Dick and Jane books that use an extremely limited vocabulary. This gets old quick if you’re over the age of 6!
- Read more interesting texts, but look up the majority of words in a dictionary. Ugh.
- Read a “diglot reader” book that shows your native language on one side of the page and your target language on the other side of the page. Better, but all the switching back and forth is still pretty frustrating.
Fortunately, there’s another option: use a “diglot weave reader”  that blends words from both languages into a single text. As shown in Figure 1, Spanish words are introduced into an English text. Even if you don’t know Spanish, you likely were able to figure out that “idioma” means “language,” “examen” means “exam,” and “palabras” means “words.” And when you’re exposed to those same words later, you can implicitly learn them without even trying!
The phrase diglot weave comes from the roots: di- (two), glot (languages), and weave (to blend two languages together). This approach, also called the bilingual reader method, substitution method, or sandwich stories, has been studied by linguists for over 70 years. A handful of theoretical and empirical studies have demonstrated the value of the approach which, in the words of its earliest proponent, leverages “the most natural and most indispensable ally in our struggle with the foreign language: our own native tongue” .
Some key research findings from studies of diglot weave readers show that:
- Readers of diglot weave texts learn many new words compared to other techniques. Using a diglot weave book led to 35% more vocabulary words learned compared to reading a challenging text solely in the target language , 75% more words compared to semantic mapping techniques , and were equally effective as computer-based drill and practice programs .
- Readers enjoy reading texts using a diglot weave . They were less frustrated and had reduced anxiety, as well as increased optimism when compared to reading a text solely in the target language . They also liked it better than semantic mappings  and a computer-based drill and practice program .
You may be asking yourself: If this approach is so powerful, why haven’t I heard of it before? The main reason is that, until recently, diglot weave texts were only available in print format — or in a static digital format. This has the major limitation that a given book cannot be customized to a specific learner’s reading level. If, for example, you read the Learn Spanish: Substitution Method Joke Book, it doesn’t take into account what words you may already know in Spanish. Another major problem is that you are limited to reading a small number of texts that someone already created in a diglot weave format — you can forget about reading today’s news or your social media feed.
Fortunately, we live in an era where any text (e.g., website, news article, social media feed) can be automatically turned into a dynamic diglot weave text on-the-fly and tuned to your personalized vocabulary knowledge. To be clear, this is a very technically demanding task, which requires knowledge of state-of-the-art machine translation and statistical “word alignment” algorithms (the topic of a future post). However, the massive amount of textual data made available via the Internet, coupled with significant advancements in machine learning make it feasible to accomplish what would have been impossible even a decade ago. Our LoomVue browser extension will finally help bring the diglot weave technique into the 21st Century!
 Bernard, W. (1951). Psychological principles of language learning and the bilingual reading method. The Modern Language Journal, 35(2), 87–96.
 Christensen, E., Merrill, P., & Yanchar, S. (2007). Second language vocabulary acquisition using a diglot reader or a computer-based drill and practice program. Computer Assisted Language Learning, 20(1), 67–77.
 Silver, M. (1997). The effect of the Book of Mormon diglot reader: A study of the vocabulary acquisition, reading comprehension, and the reduction of negative affective variables in missionaries. (Master’s Thesis).
 Simanjuntak, O. V., & Simanjuntak, D. (2018). Students’ Vocabulary Knowledge: Comparative Study Enhancing Between Semantic Mapping and Diglot Weave Techniques. Acuity: Journal of English Language Pedagogy, Literature and Culture, 3(2), 85–97. [While the quality of this article is not particularly strong, it is included for completeness].
 Ji, Y. (1999). Communicative Language-Teaching through Sandwich Stories for EFL Children in China. TESL Canada Journal, Vol. 17, №1.