Productive and receptiveThe first major distinction that must be made when evaluating word knowledge is whether the knowledge is productive (also called active) or receptive (also called passive) and even within those opposing categories, there is often times no clear distinction. Words that are generally understood when heard or read or seen constitute a person's receptive vocabulary. These words may range from well-known to barely known (see degree of knowledge below). In most cases, a person's receptive vocabulary is the larger of the two. For example, although a young child may not yet be able to speak, write, or sign, he or she may be able to follow simple commands and appear to understand a good portion of the language to which he or she is exposed. In this case, the child's receptive vocabulary is likely tens, if not hundreds of words but his or her active vocabulary is zero. When that child learns to speak or sign, however, the child's active vocabulary begins to increase. Productive vocabulary, therefore, generally refers to words which can be produced within an appropriate context and match the intended meaning of the speaker or signer. As with receptive vocabulary, however, there are many degrees at which a particular word may be considered part of an active vocabulary. Knowing how to pronounce, sign, or write a word does not necessarily mean that the word has been used correctly or accurately reflect the intended message of the utterance, but it does reflect a minimal amount of productive knowledge.
Degree of knowledgeWithin the receptive / productive distinction lies a range of abilities which are often referred to as degree of knowledge. This simply indicates that a word gradually enters a person's vocabulary over a period of time as more aspects of word knowledge are learnt. Roughly, these stages could be described as:
- Never encountered the word.
- Heard the word, but cannot define it.
- Recognize the word due to context or tone of voice.
- Able to use the word but cannot clearly explain it.
- Fluent with the word – its use and definition.
Depth of knowledgeThe differing degrees of word knowledge imply a greater depth of knowledge, but the process is more complex than that. There are many facets to knowing a word, some of which are not hierarchical so their acquisition does not necessarily follow a linear progression suggested by degree of knowledge. Several frameworks of work knowledge have been proposed to better operationalise this concept. One such framework includes nine facets:
- orthography - written form
- phonology - spoken form
- reference - meaning
- semantics - concept and reference
- register - appropriacy of use
- collocation - lexical neighbours
- word associations
- syntax - grammatical function
- morphology - word parts
Types of vocabularyListed in order of most ample to most limited:
Reading vocabularyA person's reading vocabulary is all the words he or she can recognize when reading. This is the largest type of vocabulary simply because it includes the other three.
Listening vocabularyA person's listening vocabulary is all the words he or she can recognize when listening to speech. This vocabulary is aided in size by context and tone of voice.
Writing vocabularyA person's writing vocabulary is all the words he or she can employ in writing. Contrary to the previous two vocabulary types, the writing vocabulary is stimulated by its user.
Speaking vocabularyA person's speaking vocabulary is all the words he or she can use in speech. Due to the spontaneous nature of the speaking vocabulary, words are often misused. This misuse – though slight and unintentional – may be compensated by facial expressions, tone of voice, or hand gestures.
Focal vocabulary"Focal vocabulary" is a specialized set of terms and distinctions that is particularly important to a certain group; those with a particular focus of experience or activity. A lexicon, or vocabulary, is a language's dictionary, its set of names for things, events, and ideas. Some linguists believe that lexicon influences people's perception on things, the Sapir–Whorf hypothesis. For example, the Nuer of Sudan have an elaborate vocabulary to describe cattle. The Nuer have dozens of names for cattle because of the cattle's particular histories, economies, and environments. This kind of comparison has elicited some linguistic controversy, as with the number of "Eskimo words for snow". English speakers can also elaborate their snow and cattle vocabularies when the need arises.
Vocabulary growthInitially, in the infancy phase, vocabulary growth requires no effort. Infants hear words and mimic them, eventually associating them with objects and actions. This is the listening vocabulary. The speaking vocabulary follows, as a child's thoughts become more reliant on its ability to express itself without gestures and mere sounds. Once the reading and writing vocabularies are attained – through questions and education – the anomalies and irregularities of language can be discovered.
In first grade, an advantaged student (i.e. a literate student) knows about twice as many words as a disadvantaged student. Generally, this gap does not tighten. This translates into a wide range of vocabulary size by age five or six, at which time an English-speaking child will know about 2,500–5,000 words. An average student learns some 3,000 words per year, or approximately eight words per day.
After leaving school, vocabulary growth reaches a plateau. People may then expand their vocabularies by engaging in activities such as reading, playing word games, and participating in vocabulary programs.
The importance of a vocabulary
- An extensive vocabulary aids expressions and communication.
- Vocabulary size has been directly linked to reading comprehension.
- Linguistic vocabulary is synonymous with thinking vocabulary.
- A person may be judged by others based on his or her vocabulary.
 Native- and foreign-language vocabulary
 Native-language vocabularyNative speakers' vocabularies vary widely within a language, and are especially dependent on the level of the speaker's education. A 1995 study estimated the vocabulary size of college-educated speakers at about 17,000 word families[clarification needed], and that of first-year college students (high-school educated) at about 12,000.
The effects of vocabulary size on language comprehensionFrancis and Kucera studied English texts totaling one million words and found that if one knows the words with the highest frequency, they will quickly know most of the words in an English text:
|Vocabulary Size||Written Text Coverage|
 Second Language Vocabulary AcquisitionLearning vocabulary is one of the first steps of learning a second language, yet a learner never finishes vocabulary acquisition. Whether in one’s native language or a second language, the acquisition of new vocabulary is a continual process. Many methods can help one acquire new vocabulary.
 MemorizationAlthough memorization can be seen as tedious or boring, associating one word in the native language with the corresponding word in the second language until memorized is considered one of the best methods of vocabulary acquisition. By the time students reach adulthood, they generally have gathered a number of personalized memorization methods. Although many argue that memorization does not typically require the complex cognitive processing that increases retention (Sagarra & Alba, 2006), it does typically require a large amount of repetition. Other methods typically require more time and longer to recall.
Some words cannot be easily linked through association or other methods. When a word in the second language is phonologically or visually similar to a word in the native language, one often assumes they also share similar meanings. Though this is frequently the case, it is not always true. When faced with a false cognate, memorization and repetition are the keys to mastery. If a second language learner relies solely on word associations to learn new vocabulary, that person will have a very difficult time mastering false cognates. When large amounts of vocabulary must be acquired in a limited amount of time, when the learner needs to recall information quickly, when words represent abstract concepts or are difficult to picture in a mental image, or when discriminating between false cognates, rote memorization is the method to use. A neural network model of novel word learning across orthographies, accounting for L1-specific memorization abilities of L2-learners has recently been introduced (Hadzibeganovic & Cannas, 2009).