• Meaning-focused input. This includes conversations, books, films, television and other media that you attend to primarily for their meaning. Input provides the raw data for learning new words and enriches the contextual associations of words studied deliberately elsewhere.
• Meaning-focused output. Speaking and writing are more difficult than simply understanding particular words from input, as using words correctly requires a more precise knowledge of each word and its meaning.
• Language-focused learning. This is the deliberate act of memorizing words, studying flashcards, or receiving explanations about word meanings. Webb and Nation argue that this should account for ~25% of the time spent learning a language.
• Fluency development. Finally, attention should be paid to activities that speed up the understanding and production of words already known. Familiar materials that enable quick reading or conversations on familiar topics may not be needed to build new vocabulary, but they reinforce what was learned previously.

Zipf’s Law:

How many word families do you need to know?

Here, we can take advantage of an empirical finding known as Zipf’s law. This law states that if we rank every word in a language in order from most-used (rank = 1) to next-most used (rank = 2) to least-used (rank = n), a word’s frequency of use is proportional to the inverse of its rank.

This means that the frequency of the second most common word would be roughly equal to 1/2 times some constant. In contrast, the frequency of encountering the 10,000th most common word would be roughly equal to 1/10,000 times that same constant. We would expect to see the second most common word 5000 times for each time we see the 10,000th one.

The first 1000 word families in English, for instance, account for roughly 85% of the words encountered (e.g., baby, cake, dad), and the next 1000 account for only 4.3% (e.g., background, accent). By the time you get to the 20th batch of 1000 words, they make up less than one-hundredth of one percent of the available words (e.g., abaya, chiastic).

Knowing just the first 2000 word families would cover roughly 80-90% of most novels, newspapers, conversations, television shows and academic lectures.

The upside of this finding is that you can quickly get to the point where you know most of the words being used.

The downside is that low-frequency words are often essential for understanding what is being said. Native English speakers tend to know between 15,000 and 20,000 word families. Since most of those words occur increasingly infrequently, the amount of exposure needed to learn all of them properly can be staggering.

What, then, should a practically-minded language learner focus on? Webb and Nation suggest two goals might be important:

• Knowing 3000 word families “would allow learners to understand 98% of the words in most graded reading materials, as well as 95% of the vocabulary used in spoken discourse.” Knowing 95% of the words used is often considered the threshold for understanding, so learning the 3000 most common word families is a good beginner goal.
• Knowing the 9000 most frequently used word families, which include both low- and mid-frequency words, “equates to sufficient vocabulary knowledge to understand speech and writing,” Webb and Nation continue, arguing that “differentiating between the words before and after this point is useful.”