Use of a patient's second language in psychiatric evaluation and treatment has a variety of effects. Patients frequently undergo psychiatric evaluation in their second language, yet competence in a second language varies depending on the phase of illness. Evaluation of bilingual patients should ideally be done in both their languages, preferably by a bilingual clinician or by a monolingual clinician with the help of an interpreter trained in mental health issues. Cultural nuances may be encoded in language in ways that are not readily conveyed in translation, even when the patient uses equivalent words in the second language. The monolingual clinician may clarify these nuances through consultation with a clinician who shares the patient's first language and culture or with an interpreter. In psychotherapy, patients may use a second language as a form of resistance, to avoid intense affect. Therapists may use language switching to overcome this resistance and to decrease emotional intensity, if necessary. Psychotherapy can also be affected by the attitudes toward speaking that are part of the patient's culture. Discussions with bilingual and bicultural consultants can elucidate these effects for the therapist who is unfamiliar with the patient's culture.