Wow, we should start our own school fellas.
Both MiJ and Prim have really fantastic advice.
Before I give my advice, I'd like to add to what the others have said - As a professional I would ask this employer to clearly explain what the students' backgrounds, levels and goals are. If they do not provide this, you could always make it up and tell them that you have prepared a lesson to match a fictional situation. Having this information gives you the direction you need to prepare a class. It is a shame they did not have the sense to provide it.
My company usually operates on a strictly 'customised solutions' philosophy. None of this 'business English' stuff that Prim expertly summarised.
I guess I can add the following:
1. Establish a purpose for the trainees to be there. If they don't know because their company has ordered them to be there, this can take time. Establish some goals they want to achieve both short and long term. This will depend on their level within the company.
2. Explain how achieving a workable confidence in using the language can help them reach these goals, whether they be internal or external. Become familiar with each individual's situation/goals and keep referring to them during the class to maintain motivation as much as possible.
3. It is tried and true - maximise trainees' output of the language as much as possible whilst tailoring each activity as much as possible to their goals and business environment. Agree with MiJ in setting students up for success and not failure when creating tasks.
4. I treat the members as trainees not students and I usually keep with a philosophy of 'adding value' to themselves and thus to their company. With each skill or situation they encounter and become comfortable with, they are increasing their value within the company and ensuring a greater success and profitability.
5. Discussing culture as someone has mentioned is a very favourable activity and well received by trainees. The value of this knowledge is also easily identified.
6. It is really up to you and your time, but I often ask trainees to bring authentic material from their work to class and prepare classes based on this. They should be aware of confidentiality issues though.
7. Do not insist on 'English only, at all times, death be to those who utter a Japanese word' rule. These are adults, and an emersion approach will only succeed if they are attending English lessons every day for 8 hours a day and most probably in an English speaking country. Of course, as much English as is possible and making use of all their communication 'tools', such as gesture and simplification, should be used first, but using the first language to confirm understanding is not only normal, but very productive. The final output task, however, should maximise the use of the taget language to achieve the goal.
8. Listening activities can be VERY demotivating due to the Japanese strive for perfection. Make sure you really set these up well or tailor the activity to meet the level and needs of the students. Listening and pronunciation are arguably the most difficult skills to master in a second language environment such as studying English in Japan. Even merely making the trainees aware of this can have a positive and motivating effect.
9. If, however, they are only coming to the lessons to have a break from work, have a good yarn and joke around, you can probably just ignore everything I just said after at least trying step 1 and 2 above. Such individuals will probably be satisfied if you just come into the room and say hello and make an 'oyaji' joke or two.
Hope there is something useful in my bit Jus
