English-Spanish bilinguals solved simple arithmetic problems and were required to respond In their preferred (P) language. the language In which they originally learned arithmetic, or In their nonpreferred (NP) language. Each arithmetic problem required one. two, or three addition operations. Reaction time was a linear function of number of operations. The intercept for the P language was lower than that for the NP language. but there were no differences In slope. The intercept difference was interpreted In terms of translation time. either as translation of the sum from the P to the NP language or as translation from an abstract representation to the NP as opposed to the P language.