My wife has worked as an ASL interpreter for the deaf community in the past. It was on an hourly basis. We have has full time interpreters for our ESL students from time to time, but they are paid as instructional aids I think they make about $15 / hour. so that would be $980 for the entire day. but they are working the whole day.
If they want to really rake it in, have a line of Somalis going to the doc the same day, and stack the 8 hour minimum invoices (and travel compensation) on a per patient basis. Figure 3-4 patients per hour, the total billed could get pretty deep over a day.
Patient A: 8 hr minimum + travel
Patient B: 8 hr minimum + travel
Patient C: 8 hr minimum + travel
Patient D: 8 hr minimum + travel...
And that's just the first hour or so.