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一、an average of 20,000 to 30,000 vocabulary words
①Even with intensive study, how many words do non-native speakers know? ⑴The researchers found that native adult speakers of English understand an average of 20,000 to 30,000 vocabulary words, and native speakers learn about one word a day from ages 16 to 50. ⑵In contrast, non-native speakers living in English-speaking countries for many years learn 2.5 words a day, over twice the rate of native speakers. Even with that breakneck speed, researchers found that adults know on average 10,000-20,000 words less than their native counterparts, or a native English speakers’ 8- to 14-year-old vocabulary level. ②The value of providing language services ⑴Learning a language is a lifelong pursuit: even native speakers learn a new word every day on average. Critics of immigration often say that if only immigrants took the time to learn the language of the country they immigrated to, they would integrate better. This study shows that learning a language to total fluency takes years of study and dedication, and a non-native speaker may still miss critical vocabulary. ⑵The takeaway is this: even if the patient appears to be fluent and proficient in English, there may be moments when they will need and want a professional interpreter to help them, such as in jargon-heavy medical scenarios. An interpreter can be, and often is, a lifesaver.