Marluce Vieira, Brazil
I think you could take some notes on the mistakes they make most frequently, and have a special activity to discuss that. Something you could do is prepare some short activities that relate to that every class.

Entisar Elmorsy, Brazil
Grammatical mistakes in speaking and writing is a common problem among all ages. What you can do is make your own mistakes book in which you can record the most common mistakes and discuss them with your students without refering to anyone of them in order not to embarrass them.

Ornella Rosselli-Dabool, Israel/USA
The best way to correct their error is to rephrase the correct way to say the statement, and then ask them to repeat it. After you have corrected them, and see that they understand the correct structure, ask them questions using the grammar structure, and continue to correct them. Lastly, try a role play activity to check their understanding, and then continue with the next item or lesson on your lesson plan. Remember these are intelligent adults, so they should catch on quickly, unless they are at a quite lower level. But for upper levels, this technique should work! Good luck!

Mike Hicks, Germany
I suppose the first thing to identify is if they are mistakes due to lack of knowledge. Should this be the case some revision of the basics is called for before moving on to correction methods. If on the other hand they are simply slips and they can self correct when you draw their attention to the mistakes the following method may be useful: Warn the group that you will be focusing on only one kind of error for the day and each time one of them makes that particular error, you will make a mark on the board. At the end of the lesson you can show them just how many mistakes they make and apply a bit of pressure "Next time there should be improvement...or grammar the whole lesson!" Repeat the exercise the following lesson. I have found that students very quickly become tuned in to the particular error and begin self correcting or eliminating the error after a very short amount of time.
Cheers,
Mike

Meenakshi H. Verma, India
I am teaching engineering students and I also face the same problem in my class. I give them small quizzes based on grammar, followed by any writing task like writing reports, experiments and even imaginative writing e.g. any memorable experience or a short story on a given theme.

B.Sivakami, India
Making grammatical mistakes may lead to some misunderstanding sometimes. Encourage the students to correct themselves if they come to know that they have made grammatical errors. Deliberate attempts on correcting their mistakes by themselves will bring desirable results. The teachers can mentally take note of the mistakes each student makes and give the corrected versions of them later. They can also try to make the students gently aware of the mistakes they make. Only punitive measures discourage the students from using the language they are learning.

María Argente, Spain
I understand you perfectly because I have the same kind of problem with my classes. And on top of that I teach a large class (25-27 students per class)!!
So what I do is... I use post its! When students are practising oral skills or debating in groups, I walk around the class and listen to a group. I take note of grammatical mistakes,pronunciation mistakes or translation mistakes (they are thinking in Spanish so they translate their thoughts into English literally). I don't want to interrupt the flow of the conversation so when I move to the next group, I leave the post-it note on their desks and move on to another group. At the end of the session I ask them to identify their mistake and try to correct it. We write some of the examples on the blackboard. I encourage them to have their own typical mistakes record, and keep track of their own personal slip-ups, and try to correct them in the future.
Our motto is: identify mistake, self correction and then get rid of it!!
Hope this helps!

Carlos Raul Lopez Reatiga, Mexico
Dear Angela
This is a very commom mistake at different levels. It is sometimes difficult to make students aware of that problem -making mistakes. If they are post-graduates and your concern goes into helping them avoid those mistakes you should ask yourself these questions: Do you want them to stop communicating for the sake of accuracy? In other words, Is it acceptable to sacrifice fluency for a little acuracy? Which is more important for them, as learners? Which is more important for you, as a tutor? What I would do is paraphrase and offer tangible examples, with audio or video, where lower level students make mistakes. Later on, after they have listened or watched other people's mistakes, I would ask for suggestions to correct them. This way they could become aware of the mistakes they are making and do a self analysis, consequently, they would make less mistakes.

Raffaella, Italy
Point them out to them! It's no use saying 'there are too many mistakes' if you don't tell them what the mistakes are!! If you think the students should know the mistakes they can't make, then you should a) not accept them for the course (i.e. entry test) or b) write a letter to educational authorities to highlight a literacy problem. I teach English in Italy and I find that my student make way too many grammar and spelling mistakes which should have been overcome at primary level. I find it very hard to continue with my normal teaching programme whilst trying to compensate for their writing problems! And to think that Italian children struggle with their Italian is no consolation to a teacher of English!

Yolanda Mirela Catelly, Romania
A useful way of reducing the amount of mistakes of upper intermediates might be that of organizing their normal activities focused on, for instance, debating and getting to a conclusion to be reported to the class, by having them work in pairs/small groups, with one Observer carefully listening to and even noting down the language mistakes being made. With various tasks, different students could, in turn, get the role of Observers. Then all the Observers should work together and draw up a sort of 'top ten' of the most frequent mistakes of the entire class. That would be the sensitizing part of the activity, which could then be followed by any form of remedial work, such as: correct the mistakes in a text, etc.

Girish Seshamani, India
Let us clearly understand that no one can master the English language. It is an ocean by itself. We are and will continue to be students of the English language throughout our life. I frequently come across the same concerns which you are sharing right now across all age groups. The best way to tackle this dilemma is to take a session on the common mistakes committed by learners, as far as the usage goes. At the same time, i firmly make it a point to tell them, that the day they get a feeling they have mastered the English language, they are digging their own grave.

Hazrat Umar, Pakistan
I teach speaking skills to beginner and intermediate level students. I do not correct them in the beginning because this shatters their confidence in the beginning and hampers their fluency. When once the students get confidence I note down their mistakes and tell all the students in general about the mistakes. I also sometimes ask the peers of a student to point out the mistakes of their classmate. Activities should go from easy to difficult. I think this all helps students become confident, fluent, and proficient.

Pritee, Mauritius
I teach adults and I face the same problem. You could start by:
1. identifying the most common mistakes;
2. addressing them in your class by order of priority;
3. do not address the problem only but make sure that you give sufficient support and relevant links or advice which would deter them from further such mistakes;
4. an interesting activity would be to go for directed writing or 'dictee' (dictation) as we say in french....using the problem words in a specific context or passage... They would learn to control their own writing.
This works try it out!