It was Péter Medgyes (1994) who first opened the floor for debate on this issue. For a long time, there was a well-spread “prejudice”, started with Chomsky (1965), that native speakers were better English teachers.
Scholars such as George Braine (1999) and Vivian Cook (1999) have consolidated the research in the area, striving to ascertain whether native speaker (NS) teachers are necessarily better teachers than non-native speaker (NNS) teachers. In this demystification, they have ultimately tipped the scale in favour of the latter, asserting the status of NNS teachers of English in the world.
Research has unveiled facts about NS and NNS teachers which are often very different from the layman’s perceptions:
The fact that NNS teachers of EFL have learnt their English in very much the same context as their students allows them to better predict which linguistic items would be difficult for them. A research by Arthur McNeill (in Llurda, E., 2005) where NS and NNS teachers are compared concludes that “teachers who speak the same L1 as their students are generally more accurate in identifying sources of lexical difficulty in reading texts than teachers whose mother tongue is English (…)”.
By the same token, only NNS teachers can put themselves into the students’ shoes and understand their feelings during the learning process. Thus, NNS teachers can be more patient and understanding.
NNS teachers have the advantage of being proficient enough at two languages. On the other hand, the NS who has just arrived has to struggle with a couple of words in most cases before starting the new foreign language learning process (provided they are willing to learn it). There are also cases in which native speakers of English have the belief that theirs is “the superior” language and that there is no point in learning another one.
NS teachers may have a better pronunciation or richer vocabulary but sometimes they lack teacher training. In many cases they are just foreigners working as teachers or they take a brief training course upon arrival (this is a consequence of the high status NS often enjoy among employers).
According to Arva and Medgyes (2000:261), one of the most outstanding pitfalls of NS teachers identified in a research was their poor knowledge of grammar. This research showed that NS teachers could not explain or give a scientific reason why something was right or wrong. Quite on the contrary, knowledge of English grammar was often a source of pride for NNS teachers, since they study the language in depth; thus, giving scientific explanations for correct or incorrect answers.
Additionally, NS teachers will probably be unable to teach at their students’ own pace because they will not know the difficulties a student might have with certain contents or some specific skill. They will also find it difficult to modify their English to be understood by students of lower levels of proficiency who might have difficulties in understanding because of speed or lack of knowledge and vocabulary. In this cases, the NNS has the advantage of knowing the L1 which may be used for clarification.
With globalisation and the advent of English as an international language, the very status of “native speaker” has been put to question. Braine (1999) states that “the native speaker teacher is a fallacy and linguistically anachronistic”, then he reminds us that no language is superior to another and that “language change or diversification cannot be stopped by attempts at purification or standardization”.
For further discussion of this issue, you may wish to visit the following forum http://eflclassroom.ning.com/forum/topics/non-native-vs-native-speaking