There is evidence of the importance of N400 and P600 waves in linguistic processes, theses brain waves are related to syntax. This work proposes to evaluate learning process through the analysis of responses generated when formulation of word is requested, an artificial grammar test (AGT) is developed and N400 and P600 peaks are taken as indicators of performance; and two different groups of subjects took the AGT, 5 monolinguals and 5 bilinguals.The AGT is composed by 30 hybrids, each hybrid defines rules to formulate words; then if this word accomplished the rules, it is considered as grammatical. The N400 and P600 waves are computed by each word letter, and the mean for all 30 hybrids is compared between both two groups by electrode.Greater amplitudes for N400 and P600 peaks was found for monolinguals in comparison with bilinguals.