The word frequency effect on second language vocabulary learning

Learning a second language is tough. The most efficient way to help language learners with unfamiliar texts is to first identify the difficulty level of individual words.

We know that factors such as word length, number of syllables and number of consonant clusters have been shown to contribute to the difficulty of words when people are learning their first languages. Word frequency, which approximates how many times a learner is likely to have heard or seen a given word, is a fourth variable that also influences the word difficulty for first language learners.

To see whether these factors also apply to learning second language vocabulary, and to find out which one has the most impact on word difficulty, we conducted a study using Voxy learners as our subjects.

In our experiment, we concluded that the variable that contributes the most to word difficulty for second language learners is word frequency. The more common a given word is in English, the more likely Voxy users were to know it. We also found that word length, number of syllables and number of consonant clusters did not correlate with word difficulty when we consider words of the same frequency level. These findings will inform the way Voxy uses computational models to determine word difficulty in our product going forward as well as inform future research.

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