Nov 24, 2014


How many words would you say you knew? 10,000? 30,000? All 45,000 words of the English language? How many more would you say you knew than a non-native speaker who has studied English for 10 years?

To answer this question, we’re going to look at data collected by researchers from an independent American-Brazilian research project through the website TestYourVocab.com. It was intended to “measure vocabulary sizes according to age and education, particularly to compare native learning rates with foreign language classroom learning rates.”

The test determines the vocabulary size of each test-taker by presenting him and her with spectrums of vocabulary words arranged by difficulty. They then ask the test-taker to choose the vocabulary words he or she really understands the definition for, not just recognize as a word he or she has seen. In 2013, the researchers received their 2 millionth test result and were able to put together some interesting data results.

Native Speaker Results

The researchers found that native English-speaking adults understood an average of 22,000 to 32,000vocabulary words, with 18-year-olds at 22,000 and 70-year-olds at 32,000. They found that native speakers, from the ages of 16 to 50, learn about 1 word a day, which slows down one a person enters their fifties.

Foreign Speaker Results

Foreign test-takers who lived abroad for many years knew an average range of 11,000 to 22,000 words. Researchers estimated that foreigners living abroad learn about 2.5 words a day. They found that even as adults, foreigners living in the English-speaking countries such as the US know on average 10,000-20,000 words less than their native counterparts. When comparing scores, foreigners living in English-speaking countries scored at a native English speakers’ 8- to 14-year-old vocabulary level.


One of the complaints that often arises when the question of whether to provide people with interpreters is that if foreigners only spoke English – the language of their host country – they wouldn’t need interpreters.

But, as is demonstrated out by the above statistics, sometimes learning a language can be a lifelong pursuit: even native speakers learn a new word every day on average until they reach middle age. According to the data, foreigners work more than two times as hard to learn the vocabulary of their host country, but despite their efforts, many struggle to reach the same level of vocabulary knowledge as a native speaker.

So here are the four truths that we can take from this:

  1. Learning a foreign language to native-fluency is a tremendous achievement that takes years of study and dedication.
  2. Communicating in your non-native tongue every day can be difficult, and even though you may study for years, miscommunications can occur.
  3. Having to worry about diseases and ill health for your loved ones and yourself is extremely stressful, especially if the news is delivered in a language you are still learning.
  4. Having an interpreter there to interpret for you in these situations can be, and often is, a lifesaver.

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Topics: Demographics & Culture

Written by Andy Bielat