Feedback

There are different factors that affect second language learning. Some of them are age, critical period, motivation, exposure, procedure, etc. Among them feedback is taken as an important factor so far as behaviouristic theory of language learning.
Feed back refers to any information which provides a report on the result of behaviour, commments or information that learners receive on the success of a learning task, either from the teacehr or from other learners.
Reinforcement in Stimulus-Response theory refers to a stimulus which follows the occurance of a response and affects the probability of that response occuring or not occuring again.
Reinforcement which increases the likelihood of response is known as positive reinforcement and reinforcement that decreases likelihood of a response is known as negative reinforcement.
So, it seems that reinforcement is a bit specialized term than feedback.
In the case of second langauge learning feedback plays a vital role.On the one hand it praises and encourages learners to produce correct utterances, and discourages them from making mistakes on the othe hand.
Positive or negative, both of types of feedback help learners to learn better. Positive feedback strenthens the learned linguistic behaviour whereas negative feedback avoids undesired behaviours.
Students expect positive feedback from their teachers.
It is not necessary to give feedback in the case of first language learning because they recieve in one or all of the following ways:

• Parental reward
• Trial and error
• Correct forms provided by adults
• Analogy and generalization