The processing of two-digit numbers in bilinguals.

We explored possible between-language influences when bilinguals processed two-digit numbers. Spanish/English bilinguals and German/English bilinguals performed a number comparison task with Arabic digits and verbal numbers in their first language (L1) and second language (L2) while the unit-decade compatibility was manipulated. The two bilingual groups showed regular compatibility effect with Arabic digits. In L1, Spanish/English bilinguals showed reverse compatibility effect, while German/English bilinguals showed regular compatibility effect. However, both groups of bilinguals presented reverse compatibility effect in English (L2), which suggested that the bilinguals' L1 did not determine the processing of number words in their L2. The results indicated that bilinguals processed two-digit number words selectively in their L1 and L2 and that they did not transcode L2 numbers into Arabic format. ©2011 The British Psychological Society.