1. Introduction
1.1 Research background
Among three basic language components——pronunciation, vocabulary andgrammar, vocabulary is the key part in language learning. So is the English vocabulary.English vocabulary is always the important and difficult part in language learning. As theessential factor, English vocabulary is described as the only way to convey information.So Wilkins says, limited information can be delivered without grammar, however,nothing can be conveyed without vocabulary. In Widdowson's opinion, vocabulary ischief and grammar is minor regarding the communicative function. Therefore, Englishlearning and teaching should lay great importance on English vocabulary. Yet mostcollege students’ English vocabulary hasn't reached the expected standard in neitheramount nor application according to the latest survey. Therefore, many researches havebeen carried out to study English vocabulary acquisition and English vocabulary teachingSkehan states that the more systematically and significantly the information is kept inmind, the more easily they are memorized. Furthermore, the closer connection betweenknown knowledge and unknown knowledge, the better memory occurs. According tosuch a theory, only English vocabulary adopted in real communication can it be recitedand remained for a longer period. Thus, English vocabulary teaching should adopt outputteaching method, i.e. actual communication including speaking and writing，to bringabout efficient language learning.
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1.2 Purpose and significance
Many researches have focused on output teaching method in English vocabularyteaching, while scholars only discussed related theory, the comparison of input andoutput teaching methods. In addition，the objects of study are mainly limited to primarystudents, college students with higher English level.Based on the framework of Comprehensible Output, the Theory of DepthsProcessing and The Involvement Load Hypothesis, this study combines written outputand oral output and chooses the college students with relatively poor English level assubjects, aiming at testing the efficiency of task-based output method in Englishvocabulary teaching. Experimental statistics will be expected to answer the followingthree major questions:(1). Compared with traditional teaching method (purely input or merely outputwithout task)，is task-based output teaching method more efficient for English vocabularyacquisition?(2). What is the relationship between receptive vocabulary and productivevocabulary? Compared with receptive vocabulary learning, is task-based output teachingmethod is more helpful for students obtaining productive vocabulary?(3). In conducting task-based output teaching method, are there any genderdifferences of effect on vocabulary acquisition?
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2. Literature Review
2.1 Defining key terms
As for vocabulary, different definitions could be found in different dictionaries. Onedefinition in Cambridge Advanced Learner 's Dictionary is that “vocabulary means thetotal number of words used by or known to a particular people or group of persons, allthe words in a certain language or all the terms in a certain subject”. In Oxford AdvancedLearner，s English-Chinese Dictionary, vocabulary is defined as “the total number ofwords that make up a language，，. In Longman Dictionary of Language Teaching &Applied Linguistics，vocabulary refers to a set of morphemes, including free words,compound words, idioms and expressions. In Routledge Dictionary of Language andLinguistics^ vocabulary indicates total set of all the words in a language at a particularpoint in time.As far as word is concerned, different dictionaries define it in different ways. Thebest known definition of word is given by American linguist Bloomfield (1926), whodefines a word in his article as "a minimum free form of language that is, word is thesmallest form that can be used independently，and therefore word can not be furtherdivided into smaller segments to convey information by themselves. A better way todescribe a word is probably to survey the four characteristics of a word. First of all, aword is a sound or combination of sounds which we produce voluntarily with our vocalequipment. Second, a word is symbolic, i.e. it stands for something else, such as objects，happenings, or ideas. Third, words are part of the large communication system we calllanguage. Lastly, words help human beings interact culturally with one another.
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2.2 Related theory
Considered as a symbol of second language acquisition activity, output is supposedto be useless in mastering target language (Krashen, 1985). This is doubted by manylinguists. Based on a long term of empirical researches with French immersion programin Canada, Swain (1985, 1993) proposes Comprehensible Output Hypothesis. She statesthat the comprehensible output can force learners to pay attention to the usefulexpressions and sentence structure, which possibly help learners express their own ideasclearly and successfully. Particularly, output may promote learners to deal with languagedeeply with more mental efforts than input does (Swain，1995). When learners intend toexpress more accurately and fluently，language acquisition or learning may occur throughproducing second language by either speaking or writing.According to Swain's study, output derives three functions in second languagelearning: noticing function，hypothesis testing function and metalinguistic function.
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3. Research Design ........20
3.1 Aims ....... 20
3.2 Subjects....... 20
3.3 Vocabulary level test....... 21
3.4 Materials (target words and reading passages)....... 21
3.5 Procedure of the Experiment.......22
3.6 Data collection and analysis....... 26
4. Results and Analyses .......27
4.1 Results of vocabulary test and pretest.......27
4.1.1 Results of vocabulary test .......27
4.1.2 Results of pretest....... 28
4.2 Results of the four posttests ....... 28
4.3 Receptive vocabulary and productive vocabulary ....... 33
4.4 Experimental difference on genders....... 41
5. Discussions .......44
5.1 Scores' Comparison between CC and EC .......44
5.2 Relationship between receptive and productive vocabulary....... 45
5.3 Comparison of different genders ....... 46
5. Discussions
5.1 Scores' Comparison between CC and EC
From this experiment, it can be drawn that no matter in receptive vocabulary tests orproductive vocabulary tests, students' scores in experimental class are obviouslydifferent from that in controlled class. Moreover, students in experimental class performbetter in both immediate posttests and prolonged posttests. Since other possibleinfluential factors are seriously restricted in experimental class, such results prove thattask-based output teaching method really plays a great role in students' vocabularyacquisition. Related oral practice and writing task after teaching material do influencestudents' vocabulary learning a lot.This phenomenon is in accordance with Swain's output hypothesis that oral orwritten output can lead to language acquisition and language learning. When targetlanguage is produced in form of speaking or writing, learners will notice what they wantto express or what they can express, and pay attention to the gap between these twoconditions. In such situation, learners are force to recognize what they have alreadyknown or which parts they have known. In other words, producing target language onpurpose will push learners to conscientiously distinguish variety of problems in theirlanguage expressions, try hard to find efficient ways to solve these problems. Therefore,as detailed output exercises, oral and written tasks will help students fully examine theirown problems in language acquisition, vocabulary in particular，and do their best tosearch the methods to conquer these problems so as to achieve learning success.
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Conclusion
The present study examined the effects of task-based output activities on receptiveand productive vocabulary acquisition. Base on the analyses of collected data anddiscussion, several findings can be concluded here.Firstly, output exercises can advance learners' vocabulary acquisition for students inboth controlled and experimental classes really have gained vocabulary knowledge.Furthermore, task-based output teaching method can improve learners' vocabularyacquisition better because the scores in experimental class are obviously superior to thatof controlled class no matter in immediate posttests or prolonged posttests.Secondly, receptive vocabulary is in proportion to productive vocabulary, productiveability is restrained by receptive knowledge. Task-based output can help learners retainvocabulary memory and strengthen productive ability. Comparing with receptivevocabulary acquisition, task-based output teaching method is much more suitable forlearners to gain productive vocabulary.Thirdly, task-based output teaching method can promote both girls' and boys'vocabulary acquisition, however, its effect on boys is much greater than girls. This relieson the evidence that girls' scores in controlled class and experimental class areapproximately not distinct in both receptive and productive vocabulary tests. On thecontrary, boys' scores are significantly different in almost all posttests.
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Reference (omitted)