This research explored the causal nature of the asymmetrical input of bilingual development in the first language and English as a second language between adults and children in their first language country. It explained the disparity of changeability of adults and children in second (mainly English) language acquisition in countries where English is the national language in terms of the learning process practiced in schools as well as bilingual memory. Adults’ learning experiences and structures of bilingual memory require different cognitive processes in speaking than early bilinguals and native speakers. Next, this research described the core and unique processes of developing adults’ speaking skills in English language acquisition based on theories of bilingual memory. The processes of speaking English consisted of the plan of message in their first language, frequent interlingual translations between their first language and English, and self-regulated articulation focusing on English phonology while repressing the articulation of their first language. Sociocultural interactions with a teacher and peers in the English classroom acted as a means of scaffolding.