vo·cab·u·lar·y build·ingn.

How to build vocabulary in a foreign language

Read a lot of material you mostly understand, look up the words that block the meaning or keep coming back, and review those words on a spaced schedule. Each part of that routine rests on a different line of research, and each has a limit the others make up for.

vocabulary building/vəˈkæbjələri ˈbɪldɪŋ/noun
  1. Increasing the number of words you recognise and understand when reading or listening (receptive vocabulary).
  2. Increasing the number of words you can use when speaking and writing (productive vocabulary), which usually lags behind the first.

What the research says, in brief

8,000–9,000
word families to read novels without a dictionary, at 98% known words (Nation, 2006)
10+
encounters a new word often needs while reading before its meaning is likely to stick (several studies)
47% vs 37%
average recall after spaced and after massed practice across 271 comparisons (Cepeda et al., 2006)
46%
of the different word forms in a typical English novel appear only once in the whole book (our counts)

Methods compared

No single method does everything. The table sums up what each one is good for; the guides below go into the evidence.

Main ways of building vocabulary and what the research says about each.
MethodGood forEvidenceWeak spot
Reading at the right levelMeeting words many times in context; deepening knowledge of words you half knowReaders pick up part of the unknown words, and words met ten or more times have a good chance of being learnedSlow; rare words are not met often enough
Reading with a dictionary or glossesMaking repeated encounters countRepetition paid off mainly when readers looked words up or were given the meaningLooking up everything breaks the flow of reading
Flashcards with spaced repetitionKeeping chosen words for months and yearsSpaced practice beats cramming in hundreds of experiments; recalling beats rereadingCards without context; reviews pile up if you add too many
Frequency listsDeciding which words to learn firstThe most frequent 1,000 word families cover roughly 78–84% of text and speechA list says what to learn, not how to remember it
Listening and watchingRecognising words by ear; pronunciationAbout 3,000 word families cover roughly 95% of film and TV dialogueIn one comparison, listening alone taught far fewer words than reading
Speaking and writingTurning words you recognise into words you useOne of Nation's four strands of a balanced course, each given roughly equal timeNeeds a base of words to work with

Guides