- Grammatical mistakes (mistakes of verb tenses, preposition use, etc.)
- Vocabulary mistakes (incorrect collocations, idiomatic phrase usage, etc.)
- Pronunciation mistakes (errors in basic pronunciation, errors in word stressing in sentences, errors in rhythm and pitch)
- Written mistakes (grammar, spelling and vocabulary choice mistakes in written work)
Current Status
Mistakes Made During Discussions and Activities
With oral mistakes made during class discussions, there are basically two schools of thought: 1) Correct often and thoroughly 2) Let students make mistakes. Sometimes, teachers refine the choice by choosing to let beginners make many mistakes while correcting advanced students often.
However, many teachers are taking a third route these days. This third route might be called 'selective correction'. In this case, the teacher decides to correct only certain errors. Which errors will be corrected is usually decided by the objectives of the lesson, or the specific exercise that is being done at that moment. In other words, if students are focusing on simple past irregular forms, then only mistakes in those forms are corrected (i.e., goed, thinked, etc.). Other mistakes, such as mistakes in a future form, or mistakes of collocations (for example: I made my homework) are ignored.
Finally, many teachers also choose to correct students after the fact. Teachers take notes on common mistakes that students make. During the follow-up correction session the teacher then presents common mistakes made so that all can benefit from an analysis of which mistakes were made and why.
Written Mistakes
There are three basic approaches to correcting written work: 1) Correct each mistake 2) Give a general impression marking 3) Underline mistakes and / or give clues to the type of mistakes made and then let students correct the work themselves.
Fuss
There are two main points to this issue:If I allow students to make mistakes, I will reinforce the errors they are making.
Many teachers feel that if they do not correct mistakes immediately, they will be helping reinforce incorrect language production skills. This point of view is also reinforced by students who often expect teachers to continually correct them during class. The failure to do so will often create suspicion on the part of the students.
If I don't allow students to make mistakes, I will take away from the natural learning process required to achieve competency and, eventually, fluency.
Learning a language is a long process during which a learner will inevitably make many, many mistakes. In other words we take a myriad of tiny steps going from not speaking a language to being fluent in the language. In the opinion of many teachers, students who are continually corrected become inhibited and cease to participate. This results in the exact opposite of what the teacher is trying to produce - the use of English to communicate.

