Teaching Lexis in Language Class

I have to admit that when I first read the title "Teaching Lexis" of Chapter 8 in the book Learning Teaching, I felt confused and embrassed. What is Lexis? How come I have never known this word before?  Why do we teachers have to teach Lexis in class?  Will it make any difference for the students' language learning?

After reading the chapter, I have all the answers. 

Lexis is about words. However, it is not just another word for vacabulary. It means more than vocabulary. 

As we all know, words or vocabulary are the fundation of any language. And it is the first barrier one has to overcome when coming to learn a new language. Teachers always take a lot of efforts on dealing with vocabulary in and out of class. And it is true that most of the miserable memory one has of language learning has something to do with vocabulary remembering. Vocabulary is important, yet is difficult to learn. Finishing reading the chapter, I began to think it may be because we barked up the wrong tree from the very beginning. 

Learning vocabulary is not enough. Teachers and learners have to explore deeper in words learning. That is why we have to teach lexis in class. 

When we teach beginners single words like "apple", "table" and "dog", we just need to make sure they get the words pronounced right and make connection of the words with the idea of it. However, it is not enough when learners come to the more advanced level of language learning. We should help them to creat a word net inside their head. This means when learning vocabulary, one should learn all the information about that word, like its collocations, common chunks or phrases, idioms it appears in, its synonyms and antonyms, etc. Only when we get clear knowledge of the word, we can declare that we "know" this word. Otherwise, we just know how to utter the word. It will never become our productive word. 

Teaching lexis leads students to an extensive language learning journey.  Knowing the full picture of a word helps students to express themselves much better. We don't just want to communicate, we want our mind and thoughts to be exactly heard and precisely understood. That is the reason why we have to teach lexis instead of vocabulary.