In my time in China I have taught English in one college, two primary schools, one middle school, two training centers, and one company and noticed many differences between them, but the two I want to compare here are college and company.
At my current job in a company, I teach one hour every morning Monday through Thursday to two different classes of around a dozen students each, every other morning. Sometimes they are gone for personal reasons just like at college and other times they are gone because they are too busy with work. This second one usually doesn’t happen in college since students’ primary task at school is studying, whereas students’ primary task at work is working.
One of the big problems for students in college wanting to improve their oral English is that they do not get much one-on-one time to speak English with the teacher. I taught classes of twenty to sixty students. Some I saw once a week, others once a month. But at work although I only see my students twice a week in class, I see them all day every day at work. My students at work have many chances to use English one on one with a foreigner, especially since there are several of us around. They are also required to learn English for their job and so are basically getting paid to learn English instead of paying to learn like my former college kids.
Of course when we get busy, and we’re often busy, work is the number one priority, so English gets pushed to the back burner. There is usually nothing that can be done about this.
Another advantage to teaching in a company is that you are surrounded by your colleagues all the time, so have the opportunity to correct their mistakes and observe their interactions “in the field”. You get to hear them when they use an expression like “spill the beans” or “make a killing” which is really cool. They are using something useful that you taught them to communicate with a foreigner. In a college setting you don’t get the chance to do this because the students disperse after class and go their separate ways. There aren’t many chances for Chinese college students to speak English with foreigners (that’s why you sometimes get them walking up to you on the street and asking if they can practice their English with you).
Finally one of my favorite parts about teaching English at a company, which often goes unsaid, is that there are no discipline problems. Everybody comes to class and listens because if they don’t, there could be trouble.