Native non-native voices in recordings

Language teaching works well when real life and what they are doing in the lesson is connected.

We were making some recordings for a text book, and for some reason the characters in the textbook were both Japanese, speaking away in English to each other. This is fairly inauthentic as two Japanese people would most likely speak to each other in Japanese. We were discouraged from using Japanese actors for the voices, so they ended up as two North Americans, both middle aged, acting as two Japanese university students. In terms of authenticity, it may be more authentic for two Americans to speak to each other in English, but it is pretty much impossible for any of our students to be involved in a conversation between two native English speakers. Two Japanese speakers would at least give them some kind of motivation to both speak English in class.

The more likely scenarios for them would be a conversation between a native speaker and a Japanese speaker, or a Japanese speaker and a non-Japanese non-native speaker of English. The last one seems like it would be the most likely situation in which are students will have to speak English, unless of course they end up in an English classroom with some idealistic teacher breathing down their neck and forcing them into the target language.