The ABA website links to an article in the November issue of the ABA Journal, about the lack of qualified interpreters for immigrants, entitled (what else?) Lost in Translation.
bq. These cases will multiply as immigrants continue to pour into the United States, says Chicago public defender Marijane Hemza-Placek. She represents Omar Aguirre, who was wrongfully convicted and spent five years in prison for the murder of a Chicago furniture-store owner. His conviction was based largely on a confession, now in doubt, that was elicited by a police officer who acted as a Spanish-speaking interpreter, says Hemza-Placek, who works in the felony division of the Cook County Public Defenders Office. …
bq. But unfortunately, Hemza-Placek says, there is a common misconception that simply being bilingual is enough to qualify someone as an interpreter. Certification varies widely among the states, within a jurisdiction and even from judge to judge.
bq. In some instances, anyone from a clerk to an officer is drafted to interpret a confession, and they more or less guesstimate what the suspect is saying, Hemza-Placek says. These stand-ins often have unexplored biases, and more often they lack the requisite skills.
There is a separate article on ‘Interpreting your Interpreter’, with advice on how to tell if an interpreter is qualified and competent.