Proficiency of Hisgh School Students

Which is more important to teach, grammar or vocabulary?
Traditionally, grammar is taught first; it has primacy over vocabulary. Vocabulary items were just vehicles to explain grammatical structures. In other words this kind of teaching gives primacy to form and uses lexical items simply as a way to give examples of the structures taught previously. That’s why, in most traditional textbooks, grammar comes first and it is only later that reading and vocabulary are introduced.
Recently, however, meaning has become of paramount importance in language teaching (or shall I say learning) process. As Widdowson, H. G. (1990: p. 95) points out:
Teaching which gives primacy to form and uses words simply as a means of exemplification actually denies the nature of grammar as a construct for the mediation of meaning. I would suggest that the more natural and more effective approach would be to reverse this traditional pedagogic dependency, begin with lexical items and show how they need to be grammatically modified to be communicatively effective.

Why is vocabulary important?
First, it would be easier to communicate reasonably without many problems if you could use enough appropriate vocabulary in context. However, one would undoubtedly be unable to communicate relying only on grammatical rules. What gives a structure its raison d’être is mainly the meaning it carries in the lexical words the structure is constructed with. According to Michael Lewis fluency does not depend so much on having a set of generative grammar rules, as suggested by Chomsky, and a separate stock of words as on having rapid access to a stock of lexical chunks. In the lexical approach, lexis is central in creating meaning, grammar plays a secondary role in managing meaning. The logical implication for teachers is that we should spend more time helping learners develop their stock of phrases, and less time on grammatical structures.
Secondly, a large inventory of vocabulary items is a prerequisite for reading and presumably listening ability. It is evident that one of the most inhibiting problems in reading activities is an insufficient number of familiar vocabulary items. While syntax may help with the construction of text meaning, the cornerstone of any interpretation of the meaning of any text is without any doubt the lexicon. Try to read a text with most of the words unfamiliar to you and you will get the idea that the lexicon is a major contributor to meaning.

Grammar and vocabulary are connected
As mentioned above in a traditional teaching grammar and vocabulary are taught separately as if they are separate areas of language teaching and learning. Many textbooks have separate sections of grammar and vocabulary. Grammatical structures are taught first and then lists of key vocabulary are presented separately. What this approach fails to show is the connection that exists between vocabulary and grammar. Susan Hunston, Gill Francis, and Elizabeth Manning suggest, in an article on Grammar and Vocabulary: Showing the Connections, that all words have patterns and that teachers should focus on teaching these patterns as: a way of encouraging four crucial aspects of language learning: understanding, accuracy, fluency and flexibility. Patterns contribute to the teaching of both grammar and vocabulary. They can form a part of any syllabus ,but are most logically associated with a lexical syllabus.
To conclude, language must be viewed in its totality with the different components constituting one whole. Believing that grammar must have supremacy over the other components is a fallacy that has to be corrected if we were to give an accurate account of how language works and how it should be taught.

References
Widdowson, H. G. (1990) Aspects of Language Teaching. Oxford: Oxford University Press http://myenglishpages.com/blog/which-is-more-important-to-teach-grammar-or-vocabulary/ Vocabulary
Vocabulary refers to the words we must understand to communicate effectively. Educators often consider four types of vocabulary: listening, speaking, reading, and writing. Listening vocabulary refers to the words we need to know to understand what we hear. Speaking vocabulary consists of the words we use when we speak. Reading vocabulary refers to the words we need to know to understand what we read. Writing vocabulary consists of the words we use in writing.
Vocabulary plays a fundamental role in the reading process, and contributes greatly to a reader 's comprehension. A reader cannot understand a text without knowing what most of the words mean. Students learn the meanings of most words indirectly, through everyday experiences with oral and written language. Other words are learned through carefully designed instruction.

Reference http://www.readingrockets.org/helping/target/vocabulary/ Grammar and vocabulary: showing the connections
Although grammar and vocabulary are traditionally thought of as separate areas of language teaching, new work on word patterns suggests that they can usefully be combined. All words can be shown to have patterns, and words which have the same pattern tend to share aspects of meaning. The patterns ‘V by -ing’ and ‘V as n’ illustrate this. We suggest that language teachers focus on patterns as a way of encouraging four crucial aspects of language learning: understanding, accuracy, fluency, and flexibility. Patterns contribute to the teaching of both grammar and vocabulary. They can form a part of any syllabus, but are most logically associated with a lexical syllabus.

Reference
http://eltj.oxfordjournals.org/content/51/3/208.short

References: Widdowson, H. G. (1990) Aspects of Language Teaching. Oxford: Oxford University Press http://myenglishpages.com/blog/which-is-more-important-to-teach-grammar-or-vocabulary/