The study analyzes the phenomenal occurrence of Siquijodnon-English code mixing. The respondents are parents, waiters or waitresses and/or receptionists, teachers, Human Resources Management Officers, and dealers in Siquijor province who were selected based on the five language domains. Using descriptive research design and adapting the linguistic and sociolinguistic theories, the study examined the morphological features code-mixed in Siquijonon–English. The paper also finds out that code mixing is used as a double-edged tool to effect personal, social and transactional functions which likely occur in school where bilingual and/or multilingual speakers are evident. The results reveal that the free morphemes (content words, function words and substitute words) are code mixed through intra-sentential code mixing and/or insertion. These results justify the generation of Code-Mixed Language Assimilator-Converger Theory.