Seongsil received her BA in English Literature and Language from the University of Seoul and BA in Linguistics from the State University of New York at Stony Brook. She received her MA in Speech-Language Pathology from the University of Maryland in College Park.

Seongsil is co-advised by Dr. Yasmeen Faroqi-Shah from the Department of Hearing and Speech Sciences and Dr. Min Wang from the Department of Human Development and Quantitative Methodology. She is interested in the diagnosis and treatment of language impairments in adults with aphasia. She is also interested in investigating how nouns and verbs are represented differently in bilingual minds.