Date of Completion


Embargo Period



Dr. Adrian Garcia-Sierra, Dr. Emily Myers, Dr. Erika Skoe

Field of Study

Speech, Language, and Hearing Sciences


Master of Arts

Open Access

Open Access


The present investigation reports the conditions that propel bilinguals’ double phonemic boundary, a phenomenon where bilinguals’ perception of speech sounds is affected by the linguistic context in which they are immersed, and theories that support bilinguals’ phonetic category structures while taking into consideration different auditory biases that could influence the double phonemic boundary such as contrast-effects, range-effects, and resource allocation. Thirty-three right-handed participants performed a Go/No-Go-Task. The sample consisted of 16 English monolinguals and 17 Spanish-English bilinguals. Participants were instructed to press a response button, using the right or left hand, when detecting 3 target sounds embedded in 6 background sounds. Two conditions were collected. In the Spanish phonetic context, 3 short-lag target sound consonants were embedded in 6 Spanish-like /ba/ sounds. While in the English phonetic context, the same target sounds were embedded in 6 English-like /pa/ sounds. Each background sound followed a target sound equally often, but stimulus presentation was kept otherwise random. It was explored if the perception of target sounds changed between phonetic contexts. Results demonstrated a double phonemic boundary for bilinguals, but not for monolinguals, with a right-hand advantage for bilinguals in both conditions. The degree of shift noted in bilinguals’ perceptual shift was correlated with language confidence. Bilinguals’ double phonemic boundary may be the result of resource allocation, as bilinguals were able to perform better on the perceptual task than monolinguals. Unexpectedly, monolinguals only showed right-hand advantages in the Spanish phonetic context, and left-hand responders pressed the button significantly fewer times than their right-hand responder counterparts. Executive function differences between bilinguals and monolinguals are addressed.

Major Advisor

Dr. Adrian Garcia-Sierra