A 2008 survey of adult residents' knowledge of ninety Jeju cultural words showed that only twenty-one were understood by the majority of those surveyed. Lack of heritage knowledge of Jeju is even more severe among younger people. Four hundred Jeju teenagers were surveyed for their knowledge of 120 basic Jeju vocabulary items in 2010, but only nineteen words were recognized by the majority while forty-five words were understood by less than 10%. A 2018 study suggests that even the verbal paradigm, among the more resilient parts of the substratum, may be in danger; the average middle schooler was more competent in the verb system of English, a language "taught only a few hours a week in school and in private tutoring institutions," than of Jeju.