Students are one of the most important elements in the teaching process. As the teaching object， they absorb knowledge from the teacher. Only after they digest the knowledge and turn it as their own， the teachers instructions can be considered successful. However， there are many factors that affect their learning， such as age， motivation and learning strategies. These factors of learners not only bring various influences on the way of teachers instruction but also learners learning. When people are researching these factors， the individual differences among students should taken into account. This paper focuses on two factors， age and anxiety. In the first section， it can be seen that different ages of language classroom have various ways of language learning and their achievement are quite different. Part two mainly introduces the anxiety feeling of the learner and how it influences the process and outcomes of second language learning in the classroom.

Age makes the difference. In the research of second language acquisition， the study of the relationship between learners age and language achievement is usually essential and unavoidable. Students who learn the second language at an early age are called early beginner， on the opposite， late beginner. The language learning process in younger learners classroom and the one in older learners classroom are quite different. Younger learners learn language in a more implicit and unconscious way， they obtain the language by receiving massive input and memorizing it （Nikolov and Djigunovic， 2006）. On the contrary， older learners rely more on explicit learning that requires them to identify language rules and understand declarative explanations. In this process， cognition plays an important role. The cognitive ability of the older learners is better than young learners， and this cognitive maturity enables them to learn， accept and absorb the declarative knowledge easier and faster. Krashen， Long and Scarcella （1982） agreed that the efficiency and learning rate of the older learners are both higher than younger learners. Ellis （1985） rated three groups of learners with the second language acquisition rate， the fastest group is children between the ages of 12 and 15， then are the children over the age of 15， the last and slowest group is 6-10. Munoz （2010） also declared in her research that the efficiency of older learners is greater than the younger learners in a short period. As a result， older students are more accustomed to the classroom environment and it is more conducive to their study， however， the younger students need to pay more efforts.

Although older learners show their favorable advantage in the process of language learning， scholars still cannot make an agreement on the ultimate attainment. Lenneberg （1967， quoted in Gui， 2011） proposed the concept of “critical period hypothesis”， he believed that from age 2 to puberty （10-12）， children enter a crucial period that they can learn a language quickly and succeed easily. After this period， this kind of advantage may diminish gradually， and language learning becomes increasingly difficult， similarly， Penfield and Roberts （1959， quoted in Marinove-todd et al.， 2000） also pointed out that the best time to learn a language is the first decade of life. These assumptions lead to a point that the younger the learner begins to contact the second language， the higher their achievement in language is likely to be. Nevertheless， Munoz （2010） concluded that being exposed to the second language early may have some positive effects but it does not imply a high level of achievement in the future. The implicit learning of younger students requires massive input， immersive environment （DeKeyser， 2000， quoted in Munoz， 2010） and also， a long period to take effect （DeKeyser， 2000）. But it is hard to achieve in the classroom setting. When their needs cannot be satisfied， younger learners advantages are difficult to maintain， and the gap between young learner and old learner is likely to disappear， and their outcomes of the second language may also reach the same state （Nikolov & Djigunovic， 2006）. Besides， early second language learning is not suitable for every young learner （Nikolov & Djigunovic， 2006）， the language learning actually depends on their ability， the more ability they are， the more knowledge they can learn. A number of adults who started learning the second language after puberty also can achieve the ultimate attainment （Nikolov & Djigunovic， 2006）. Hence， whether the second language learning in critical period decides the final achievement is still in doubt.

But there are still different outstanding outputs in younger students learning and older students learning， this section will discuss the outputs of vocabulary and pronunciation of different ages learners. As aforementioned， junior students rely more on memory mechanism while senior students get used to explicit learning， so researchers are more inclined to the view that older learners outperformed than younger learners in vocabulary learning. In Cummins and Swains research （1986）， older learners obtained more lexis than younger learners in the same teaching hours. Lasagabaster & Doiz （2003， quoted in Munoz， 2006） draw a conclusion that after a similar length of language teaching， the older students have the greater ability to use complex words in writing. Similarly， Miralpeix （2002， quoted in Munoz， 2006） founded out that the lexical gains of older students are better than younger students after 200 hours of instructions. Thus， older students takes less classroom time to learn vocabularies. Nevertheless， their superiority in lexis learning cannot apply to other aspects of learning that unrelated to cognitive， like pronunciation or oral fluency （Munoz， 2006）. Although the old learners perform well in the vocabulary aspect， they have no advantage in pronunciation. Cenoz （2002） stated that the younger objects score in pronunciation is much higher than the older objects. Munoz （2006） noticed that the pronunciation advantage of older learners usually disappears after six weeks of study， and it is due to their pronunciation is impacts by their first language. Young learners imitate the pronunciations better while older learners prefer to find close pronunciations from their first language; thus， it is difficult for them to pronounce the sounds that are not in the mother tongue. Take Chinese learners as example， Pinyin does not have the sound of [θ]， so many learners use the pronounce [s] instead of [θ] （Liu， 2008）. Xies research （2012） also proved that young learners have a higher pronunciation level. To sum up， younger learners may perform well in implicit knowledge while older learners obtain more outcomes in explicit knowledge.

Anxiety is another crucial factor that affects learners language learning. According to Spielberger （1983， quoted in Zheng， 2008）， anxiety is a subjective feeling of tension， fear， worry that relates to the nervous system. Language anxiety， which defined by Horwitz， Horwitz and Cope （1986）， is a “distinct complex of self-perceptions， beliefs， feelings， and behaviours related to classroom language learning arising from the uniqueness of the language learning process”， it sometimes has negative effects on the process of language learning. MacIntyre （1998， quoted in Zheng， 2008） regarded language anxiety as a negative emotional response during language learning and using. In the process of language learning， there are three types of anxiety： input anxiety， processing anxiety and outcome anxiety （Bailey， Onwuegbuzie & Daley， 2000）. Input anxiety indicates students nervousness when they are facing unfamiliar or new knowledge. Processing anxiety exists in the process of acquiring and digesting knowledge， and outcome anxiety implies students fear of showing their language acquirement. Worde （2003） also listed five reasons that causing anxiety in language learning： （1） non comprehension; （2） speaking activity; （3） pedagogical and instructional practices; （4） error correction ; （5） native speaker. Among these factors， learners anxiety generally associated most with the speaking activities in the classroom. As Zheng （2008） noted that students anxiety increase when the students are asked to complete an oral task， likewise， Horwitz （2001） also believed that the communicative language classroom is easier to arouse students anxiety. Because anxious students often have difficulty expressing themselves （Gardner and Maclntyres， 1993）， so they tend to underestimate their abilities， fear and reluctance to use the language proactively in class. Another effect is， anxiety diverts learners attention， Eysenck （1979， quoted in Maclntyre， 2002） mentioned that there is a positive correlation between anxiety level and learning distraction.

The period of highest anxiety in language learning is often be considered the early stage of learning.

In Maclntyre and Gardners view （1993）， anxiety gradually falls with increasing experience and proficiency， hence， if students start from the same starting line， then the lower-grade students are more anxious than high-grade students. However， anxiety levels vary from student to student due to individual differences. According to Bailey， Onwuegbuzie & Daley （2000）， the non-novice learners possess a higher level of input anxiety， processing anxiety and outcome anxiety. That is because they pay more attention to language accuracy. They are unwilling to speak， read or write the second language they are unsure of. Therefore， older beginners generally have a very high level of language anxiety. The anxious feeling will， at the same time， influence expected learning outcomes （Gardner & Maclntyre， 1993） owing to it distracts learners attention. It impedes the learners from acquiring knowledge. The more anxious they are， the less knowledge they obtain， thus their language competence cannot be improved， and it ends up again with the increase of anxiety （Worde， 2003）. In addition to this， high level of language anxiety may inhibit motivation for language learning （Gardner & Maclntyre， 1993）. It can be concluded from this vicious circle that students with high-level anxiety perform worse in class and get lower language outcomes， furthermore， the feeling can frustrate them and bring other negative impacts. So it is not only the students job to relieve anxiety， but also teachers. Teacher should notice students linguistic threshold， create an active classroom atmosphere to students and give them trust， support and interest （Horwitz，2001）.

To sum up， this paper discuss two important learner-related factors in the classroom language learning， one is the age， the other is the leaners anxiety. It is necessary to learn that the individual differences will surely cause a variety of effects on language learning. Part one compares the language learning of younger learners and older learners and get the conclusion that younger learners learning process is implicit while older learners is explicit， moreover， older learners are more productive than younger learners because of the cognitive maturity. The study of language outcome focuses on lexis and pronunciation. Through the researches， younger learners are better at phonetic aspect and older learners are specialized in lexis and grammar learning. Part two is about learners anxiety， it is a very common emotion in language learning. Too anxiety often has a negative effect on language learning process and outcome. Language anxiety makes students unable to absorb the knowledge they supposed to get in the learning process， moreover， their perform worse in the learning outcomes. As a result， students and teachers need to make efforts to relieve students negative anxiety. But what should be mentioned is that the research cannot be applied to everyone， it is more important to consider individual differences during language learning.

References：

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【作者簡(jiǎn)介】王歲云，英國(guó)南安普頓大學(xué)。