By reading the book Principles of Language Learning and Teaching, written by H. Douglas Brown, the reader is led to refl...

One of the most fruitful areas of learner language research has focused on the variation that arises from the disparity between classroom contexts and natural situations outside language classes. As researchers have examined instructed second language acquisition, it has become apparent not only that instruction makes a difference in learner’s success rates but also that the classroom context itself explains a great deal of variability in learners’ output.

It is not quite common to encounter in a learners’ language various erroneous features that persist despite what is otherwise a reasonably fluent command of language.

The relatively permanent incorporation of incorrect linguistic forms into a person’s second language competence has been referred to as fossilization. Fossilization is a normal and natural stage for many learners, and should not be viewed as some sort of terminal illness, in spite of the forbidding metaphor that suggests an unchangeable etched in stone.

Students often make errors because of a misleading explanation from the teacher, faulty presentation of a structure of word in a textbook, or even because of a pattern that was rotely memorized in a drill but improperly contextualized.

One of the major contributions of learner language research has been its recognition of sources of error that extend beyond interlingual errors in learning a second language.