1. “They are mostly interpreters because they happen to speak two languages.” In other words, they’ve been recruited from among bilinguals who aren’t ordinarily Professional Interpreters.
2. They haven’t been briefed in advance.
“Most of them are learning on the spot, and sweating with that uneasiness that is a powerful depressing factor that you simply don't understand for a while what they are all talking about, starting with the people speaking your mother language…although I know that local technicians understand and are helpful… to raise the level of understanding of the confused terp devoid of an engineering diploma…The need for interpreters to know and understand what’s being talked about is one of the factors least understood by lay people.
I know the argument of ‘no time’ which is true, but there is enough time for a one hour briefing. I know the puzzled look back meaning: ‘But you speak the language don't you?’, to which the urge to shout back a ‘It's the context stupid, the language comes next!’ bursts inside."
3. “They are all male, not for religious and social reasons… in a massively female profession.” An interesting topic, but too big to go into it here. And it mainly concerns Professional Interpreters.
Anyway, read the post in full. You can get to it via the Liaison Interpreting in Japan link on the right.