As an effective medium of international communication, English language has been
making a considerable contribution to the increasing development of various fields of
people’s life such as economy, politics, culture, science, education and international
relations. Indeed, to meet the increasing demands for the development and integration of the
country into the greater English-speaking world, over the last two decades, English language
teaching and learning have been carried out throughout the country, not only at tertiary level
but also at secondary and primary education. Many Vietnamese linguists, educators and
researchers have been doing their best in order that the quality of English language learning
and teaching at all educational levels will be greatly improved for the time being.
However, at upper secondary schools, the teaching and learning of English language in
general, English vocabulary in particular are still far from satisfaction as students’ final
results in most English examinations remain unchanged at low level. In fact, most secondary
school students have not paid enough attention to vocabulary learning as they mainly receive
basic lessons of grammar together with four skills from their teachers and textbooks. It is
common knowledge that vocabulary has a very important role to play in the language
learning process and in language use as Wilkins (1972: 11) has claimed that “without
grammar, very little can be conveyed, without vocabulary nothing can be conveyed”. Also,
vocabulary can function as the cohesive device that links the four skills of listening,
speaking, reading and writing all together. Thus, vocabulary deficiency will lead to
deficiency in other language skills.
Though vocabulary is vitally important to mastering any foreign languages, in reality,
many grade 10 students’ English vocabulary is stilllimited even though they have learned
English for four years at the lower secondary schools. It is their limited vocabulary that
explains their poor performance in using English and in their test performance. All these
have motivated me to conduct this quasi-experimental research on the topic given, namely
developing grade 10 students’ English vocabulary through extensive reading.