abstract: The presence of two copula verbs (ser and estar) in Spanish has caused a semantic competition between the two. This semantic competition has been documented from the XII century (Vañó-Cerdá, 1982). Some scholars (Brown & Cortés-Torres, 2012; Cortés-Torres, 2004; Gutiérrez, 1992; Ortiz-López, 2000; Silva-Corvalán, 1994) have demonstrated the presence of this competition in which estar has been occupying structures traditionally reserved for ser in different Spanish varieties. This study investigates the extent to which the extension of estar to contexts previously limited to ser is present in the Spanish of Puerto Rico in adjectival structures (copula + adjective). The investigation analyzed 21 Puerto Rican Spanish speakers, who completed five different instruments (interview, description of a picture, 2 questionnaires and grammar judgment). Nine of the participants completed the five tasks and the other 12 completed the 2 questionnaires. A multi-variable and qualitative analysis were employed to examine the linguistics (class or individual frame of reference, copulas the adjective allows, animacy, susceptibility to change, and type of adjective) and social factors (sex, age, level of education, and bilingualism) that favor the phenomenon. The results showed that type of adjective, copulas the adjective allows, susceptibility to change, and type of questionnaire favored the innovative use of estar. Both analyses showed a clear tendency of the linguistics factors that favor the innovative use of estar. The results of this study concur with previous studies (Cortés-Torres, 2004; Gutiérrez, 1992; Ortiz-López, 2000; Silva-Corvalán, 1994) about the phenomenon in other monolingual and bilingual Spanish dialects. This study confirms Puerto Rican Spanish follows the internal change tendency in Spanish language about the uses of ser and estar. The use of different instruments for data collection provides a clear view of the phenomenon in Puerto Rican Spanish. The use of questionnaires with confirmed estar predictors shows that some adjectives resist the phenomenon more; even with the perfect conditions for the use of estar, the participants did not allowed its use. / Dissertation/Thesis / M.A. Spanish 2013