No matter how good grammatical and phonetic skills of a speaker are, without developed lexical skills it is hard to build sentences and comprehend messages, whether oral or written.
When one learns a new word and starts using it in speech, he/she might notice that this word appears more often in oral and written contexts. This phenomenon is not unique to learners of a second language and frequently happens in ones native language context as well. In case a learner starts using new word often he/she cant help ignoring the new word in every cluster of speech that contains the word. The thing is the new word could have been often overlooked by the learner before he/she fully understood the meaning of the word and learned to identify different connotations of such a word within a specific context. In my opinion, noticing the new word more often, both in oral and written contexts, depends largely on the learners perception. A learner starts recognizing the new word and pays attention to its specific meaning when he/she knows its general meaning. For instance, the word "destination" can have lots of connotations, such as a goal or a mission, but a learner frequently uses this word only in a specific context and doesnt notice using it much. Thus, one tracks the word down every time he/she experiences the new connotation of the word. This, in turn, builds up the feeling that such a word is more frequently used by other speakers than before. As a matter of fact, people always tend to identify things they know something about in the first place and neglect things they know little or nothing about. The same is true when it comes to the learning and using of new words, both in a native language and in a second language