From the current available research, it is evident that further evidence is needed to understand Second Language Acquisition (SLA) processes under planned bilingualism approaches in English as a Second Language (ESL) environments. This study employs an explanatory single case strategy to investigate the oral proficiency and SLA experiences of a native-like English speaker brought up by second language (L2) English-speaking parents in a Spanish-speaking country. The main participants were Victoria, a 27-year-old, and her father Rafael who chose a planned bilingualism approach for her daughter's upbringing in Colombia. Data collection instruments included 51 questionnaires and 2 individual semi-structured interviews. The findings suggest that the concepts of English nativeness and language ownership ought to be based on categorisations of language expertise or proficiency rather than on other categorisations such as country of origin, nationality or the number of languages people speak. Impersonal L2 input sources such as films seem important in a learner's SLA process. Parents' involvement with the target language and interest in its culture are also important in a learner's successful SLA process in ESL environments.