Eh? If you are from Japanese decent no one should notice that you are actually from an English speaking country? Unless ofcorse , you have a noticeable namari and the people around you are just gomakakashitenno?
And I disagree about not using it in regards to other peoples feelings, in fact ,even thinking about not using it is wrong.
And how do you do an English lesson in Tajima-ben? I didn't understand that.
I didn't think it was odd for foreigners of Asian descent to be spoken to in a manner different than those who are more visibly non-Japanese, regardless of their actual ability, particularly in situations when the one's "foreignness" is not universally known. For example, my taiko group treated me completely differently than the white guy in our group on our first days, even before they knew how much Japanese we spoke.
If I have one area of my Japanese that I'm confident in, it's my speaking and hearing. My writing and reading are god-awful. At the risk of tooting my own horn, all the work I put into properly pronouncing words and adopting the local dialect and speaking cadence allows the Japanese around me to speak at their normal rate and in the dialect they're comfortable in. It doesn't mean I understand everything, but they're not slowing down for me in meetings.
When I said a local dialect isn't the kind of language you use when concerned with another's feelings, it was more in reference to speaking in proper polite Japanese. Occasionally I'll have teachers use keigo with me when asking for favors or requesting a change. That's what I meant in terms of not using a dialect.
I work with elementary school children through JET. This means there's no dedicated Japanese English teacher and most of the homeroom teachers don't understand English. I'm also working with children as low as 1st grade, which means they have no background in English. Giving instructions, especially for the games, is basically impossible without using Japanese. I've found it easier to speak in the local dialect because it's faster and it's what the kids are used to. It also works that way with my junior eikaiwa (1st and 2nd graders).
My Board of Education offered no restriction regarding the use of Japanese. The one school that requests I keep my Japanese to a minimum has their music/home ec/band teacher accompany me to class (small school, only 3 classes a day) and act as the JTE while I operate solely in the ALT capacity. Obviously, having extra teachers makes the class go much more smoothly, but a separate JTE is not a luxury most ES's can afford, particularly in the countryside.
I do believe, however, that most JHS teachers are asked to keep their Japanese outside of the classroom. When I start adult English class next month, I believe I'll be making a similar attempt to speak only English.