With instrumental motivation, the purpose of language acquisition is more practical, such as meeting a requirement for school or college graduation, seeking for a job, reading technical and scientific materials, doing translation works, doing some traveling etc。 While both integrative and instrumental reasons are essential elements of success, it is integrative motivation that has been found to sustain long-term success sustainable when learning a second language (Taylor, 1977:98)。 It is thought that students who are most successful when learning a target language are those who like the people that speak the language, admire the culture and have desire to become familiar with or even integrate into the society in which the language is used (Falk, 1978:45)。

As is shown, various definition of motivation have been suggested over the decades and since researchers define motivation from different perspectives, it has been classified into various kinds: such as internal and external, integrative and instrumental, intrinsic and extrinsic, etc。 

2。2 Theoretical Basis of Motivation

Motivation is one of the most important factors that influence students' achievements of learning a second language。 Scholars at home and abroad do many researches on motivation, so in order to furthermore understand the foreign language motivation, it is necessary to first acknowledge foreign language learning theory, the definition of motivation, the classification of motivation, and the function of motivation。 

Because of the complicacy and multifaceted nature of the motivation, there have been lots of theories about it。 Among the different theories, the most influential ones are Gardner's motivation theory and Dornyei's three-level categorization。

    Attribution theory deals with how the social perceiver uses information to arrive at causal explanations for events。 It examines what information is gathered and how it is combined to form a causal judgment” (Fiske, & Taylor, 1991:51)。 Attribution theory is concerned with how and why ordinary people explain events as they do。 Heider didn’t so much develop a theory himself as emphasize certain themes that others took up。 There were two main ideas that he put forward that became influential: Internal Attribution is the process of assigning the cause of behavior to some internal characteristic, rather than to outside forces。 When we explain the behavior of others we look for enduring internal attributions, such as personality traits。 For example, we attribute the behavior of a person to their personality, motives or beliefs。 External Attribution is the process of assigning the cause of behavior to some situation or event outside a person's control rather than to some internal characteristic。 When we try to explain our own behavior we tend to make external attributions, such as situational or environment features。

Goal Setting theory (Dornyei, 2012:21) operates on the premise that inpiduals create goals by making careful decisions to do so and are compelled toward those goals by virtue of the goal having been set。 Basically, Locke's theory states that if an inpidual sets goals, he will be motivated to achieve those goals by virtue of having set them。 Several elements must exist in order for the goal-setting effect to take place。 Goals must be clear, challenging and attainable, and there must be some method of receiving feedback。 Locke finds that the goal itself is not the motivator, but rather the perceived difference between what was actually attained and what had been planned for。

Self-Determination Theory (SDT) represents a broad framework for the study of human motivation and personality。 SDT articulates a meta-theory for framing motivational studies, a formal theory that defines intrinsic and varied extrinsic sources of motivation, and a description of the respective roles of intrinsic and types of extrinsic motivation in cognitive and social development and in inpidual differences。 Perhaps more importantly SDT propositions also focus on how social and cultural factors facilitate or undermine people’s sense of volition and initiative, in addition to their well-being and the quality of their performance。 Conditions supporting the inpidual’s experience of autonomy, competence, and relatedness are argued to foster the most volitional and high quality forms of motivation and engagement for activities, including enhanced performance, persistence, and creativity。 In addition SDT proposes that the degree to which any of these three psychological needs is unsupported or thwarted within a social context will have a robust detrimental impact on wellness in that setting。