In the system of linguistic means vocabulary is one of the most important components of linguistic competence. Knowing a word is the key to understanding and being understood. This proves the urgency of the topic given above. The importance of the lexis has been emphasized and the problem of its acquisition has been surveyed in the works of leading method ologists, scientists and teachers such as I.S.P. Nation, S. Thornbury, I. Beck, M. McKeown, A. Vermeer, J.C. Richards, B.D. Seal and others.
Vocabulary is not a developmental skill that can ever be seen as fully mastered. The elaboration of vocabulary is something that extends across a lifetime. The acquisition of vocabulary is essential for successful language use because, without an extensive vocabulary, it is unable to use the structures we have learned for comprehensible communication. The process of assimilating vocabulary is not as easy as it seems.
Knowing a word includes a wide set of its features such as form, pronunciation, spelling, meaning and use, which are mastered with the help of a five-step model for vocabulary learning. This model for vocabulary learning includes: encountering new words, getting the word form, getting a clear image, learning the meaning of the words, using the words. Renaming these steps, vocabulary learning strategies can be grouped into processes: receiving, recognizing, retaining, retrieving, and recycling in four language skills. The next consideration in delineating the construct of "vocabulary" in research and practice is that individuals have various types of vocabulary that they use for different purposes. Failure to distinguish among the different kinds of vocabulary can lead to confusion and disagreement about instructional implications. All the vocabulary that should be practically acquired by pupils in order to provide their productive and receptive performance is called real.
No matte how extended the real vocabulary is, it could not be enough for unimpeded reading and speaking, as there are always words which you do not know. The extension of potential vocabulary helps to recognise and understand vocabulary units which are met at first but could be easily comprehended. In order to teach pupils to guess potentially known words, certain methods and approaches are singled out. Among them are understanding of derivative and compound words, exploration prefixes and suffixes, understanding of unknown meanings of poly semantic words, acquisition of vocabulary through context. All these approaches are used in vocabulary learning strategies and methods of vocabulary acquisition. To analyze vocabulary teaching methods in more detail, scientists classified common techniques into four categories: de-contextualising (word lists, flashcards); semi-contextualising (word grouping, association, visual imagery, keyword, physical response); fully contextualising (reading, listening, speaking, writing); adaptable (structured reviewing).
Foreign language learners may use different strategies to acquire the target language word knowledge, but all of them require a good memory, as memorization is essential for vocabulary learning. If words cannot be remembered, few are likely to be produced properly. After students have seen or heard a new lexical item for the first time, they will need opportunities to become more familiar with it, to practice recognizing, manipulating and using it. Exercises on lexis include matching pictures to lexical items; matching parts of lexical items to other parts; matching lexical items to others, e.g. collocations, synonyms, opposites; using prefixes and suffixes to build new lexical items from given words; classifying items into lists; using given lexical items to complete a specific task; filling in crosswords, grids, diagrams; filling in gaps in sentences; memory games. To sum up, a good vocabulary exercise focuses on useful words, preferably high frequency words that have already been met before; focuses on a useful aspect of learning burden; gets learners to meet or use the word in ways that establish new mental connections for the word; involves the learners in actively searching for and evaluating the target words in the exercise; does not bring related unknown or partly known words together.