Current Research and Practice in Teaching Vocabulary

There are three approaches to vocabulary instruction and learning: incidental learning, explicit instruction and independent strategy development.
Definition
A word: is defined as including its base form, inflection and derivatives.
Incidental learning: The teacher provides opportunities for extensive reading and listening. (for more proficient intermediate and advanced students)
Explicit instruction: Diagnosing words learners need to know, presenting words for the first time, elaborating word knowledge and developing fluency with know words. (best for beginning and intermediate students who have limited vocabulary)
Independent strategy development: Practicing guessing from context and training learners to use dictionaries. (Dictionary training should begin early in the curriculum)

Incidental learning
Principle1: provide opportunities for incidental learning of vocabulary
Although most research concentrates on reading, extensive listening can also increase vocabulary learning. L2 learners can be expected to require many exposures to a word in context before understand its meaning. Low-proficiency learners can benefit from graded readers because they will be repeatedly exposed to high-frequency vocabulary.

Explicit instruction
Principle2: diagnose which of the 3,000 most common words learners need to study
Knowing approximately 3,000 high-frequency and general academic words is significant because this amount covers a high percentage of the words on an average page.
Principle3: provide opportunities for the intentional learning of vocabulary
The first stage in teaching these 3,000 commonly begins with word pairs in which an L2 word is matched with an L1 translation. Translation has a necessary role in L2 learning, but it can hinder learners’ progress if it’s used to exclusion of L2-based techniques. When teaching unfamiliar words, teachers should consider the following: 1. learners should see not only the form bit also the pronunciation and practice saying the word aloud. 2. Start by learning semantically unrelated words. Also avoid learning words with similar forms, closely related or contrast meanings at the same time. 3. it’s more effective to study words regularly over several short sections than to study them for one or two longer sessions. Repetition and review should take place almost immediately after studying a word for the first time. 4. Study 5-7words at a time. 5. Use activities such as keyword technique to promote deeper processing. 6. A wide variety of L2 information can be added to the word cards for further elaboration.
Principle4: provide opportunities for elaborating words knowledge
Knowing a word means not just knowing the translated meaning but also related grammatical patterns, lexical sets and how to use words receptively and productively. Receptive knowledge means being able to recognize one of the aspects of knowledge through reading and listening. Productive knowledge means being able to use it in speaking and writing.
Principle5: provide opportunities for developing fluency with known vocabulary
Fluency-building activities recycle already known words in familiar grammatical and organizational patterns so that students can focus on recognizing or using words without hesitation.

Independent strategy development
Principle6: experiment with guessing from context
To guess successfully, learners need to know about 19 out of every 20words (95%) of a text. a procedure of guessing begins with deciding whether the word is important enough to warrant going through the e subsequent steps. 1. Determing the part of speech of the unknown word. 2. look the immediate context and simplified it if necessary. 3. Look at wider context. 4. Guess the meaning. 5. Check out the guess is correct
Principle7: examine different types of dictionaries and teach student how to use them
Bilingulized dictionaries may have some advantages over traditional bilingual or monolingual dictionaries. Bilingulized dictionaries essentially do the job of both bilingual and monolingual dictionaries. The learners’ attention should a;so be directed toward those good sentences to learn collocational, grammatical and pragmatic information about words.

Reference
Hunt A. and Beglar D. (1998). Current Research and Practice in Teaching Vocabulary. In Richards, J. C. and Renandya, W. A. (Eds)Methodology in Language Teaching(pp. 258-266) Cambridge: Cambridge University Press.

R:Current Research and Practice in Teaching Vocabulary
I agree what a word includes translated meaning, base form, inflection and derivatives so learners should learn those related knowledge when they are learning a word. I also think extensive reading and listening could expose learners to high-frequency words so they have chances to remember them when it comes to explicit instruction, it‘s a important fact that learners know base 3,000 to support them in extensive reading. What’s more, by those fluency-building activities, students could use those intentional words more fluently and we need to elaborate related knowledge of vocabulary, too. However, I don’t think that “Start by learning semantically unrelated words. Also avoid learning words with similar forms, closely related or contrast meanings at the same time.” If learners are very beginners, we had better not confuse them with related words but if learners know numbers of vocabulary, we had better teach those related words to help them tell those differences and make them memorize those words systematically. I tutor my students mainly by explicit instruction to build their knowledge about intentional words because they are low-intermediate learners. At the same time, I’ve built their strategy of guessing the meaning from context and reinforce the importance of sentences as learning vocabulary. Now, they start to pat more attention to sentences which was listed on vocabulary list. Then I plan to ask them read a short article every week to have them expose to high-frequency words by extensive reading.