If you are lucky enough to work in a hospital where 95% of the patients speak English you always use a translator phone service whenever someone needs one. The hospital will be happy to pay for the service rather than have you stumble through the interview in a language you half understand.
However as soon as more than 10% of the hospital starts speaking Spanish, suddenly there is no translator service available. Its not financially practical and, in my experience, the hospital's response is to just not provide the service in any way accessibly to residents or students and to let you deal with the consequences. Don't get me wrong, the translation services do exist, otherwise how could they blame you for not calling a translator when you miss it an important piece of the history? However they're so inconvenient that you will be waiting for an hour to obtain services for one patient, while you will be held responsible for rounding on up to a dozen Spanish language only patients in the 90 minutes before morning report. At one 500 bed, 50% Spanish speaking hospital I worked at there were couldn't have been more than 6 translators for the entire hospital. The did 'Spanish rounds' with attendings continuously for most of their 8 hour shift and were essentially unavailable for anything other than consents and discharge planning. Another hospital used a translator phone service... which was accessed by calling a guy who had to walk the phone up to you to make sure the call was 'accounted for'. Only in EDs have I seen residents with consistent, convenient access to translation services.
In my experience resident who don't know any Spanish in those hospitals frequently end up with an even worse option than taking a history in beginner Spanish. Maybe you wait 30 minutes for the nurse whose grandmother spoke only Spanish so she kind of speaks a few words, and you leave a hour later than everyone else because you need to wait for that nurse multiple times a day. Maybe you translate through the patient's 7 year old child. Maybe you (and I have seen this often) rely on those kinds of translators for H&Ps and discharges and simply leave the subjective section entirely blank for inpatients. All your options will suck.
BTW I recommend these guys:
www.ecela.com. A vacation month + an elective month gets you 8 weeks of training. That should get you up to speed.