This study examines language preference and selection during nurse-patient service encounters as well as the motivations and effectiveness of such selection by nurses at Adeoyo Teaching Hospital, Ibadan. The study adopted quantitative and descriptive research using a self-designed questionnaire administered to a sample population of fifty (50) nurses selected using stratified random sampling. The data assessing the four phases of nurse-patient service encounters was analyzed using simple percentages and then subjected to a descriptive analysis using Peplau's (1997) Theory of Interpersonal Relations and Giles' (1991) Communication Accommodation Theory. The study finds that language preference at the orientation phase of the nurse-patient service encounters was Yoruba (20%), Yoruba and English Language (56%), while only (24%) opted for the use of the English Language. During the identification and exploitation phases, (86%) adopted the Yoruba language, while (4%) and (10%) adopted English and Nigerian Pidgin English (NPE), respectively. During the resolution phase (80%) adopted the Yoruba Language, while (16%) and (4%) used the English Language and NPE, respectively. Language preference by nurses at the different phases of service encounter, therefore, is Yoruba followed English and then NPE during healthcare provision. Nurses’ motivations for converging or diverging to and from the patients’ preferred language were on the grounds of faster healthcare delivery (96%), emotional stability of the patients (96%), level of education (100%), prestige (64%), ease of communication and comprehension (99%), detailed information (88%), language preference (62%), and patient’s language competence(62%). The Yoruba language was found to be effective during orientation, identification, exploitation, and resolution phases of nurse-patient service encounters as it was considered to depict nurses as emphatic (80%), achieve delivery of patient-centred healthcare (88%), a more coordinated service delivery (84%), effective patient evaluation as well implementation of treatment (98%). Yoruba was also found to keep patients emotionally stable (96%) and ensure effective follow-up of healthcare delivery (100%). The study has shown that linguistic affiliation by the selection of patient’s language preference, which is often the use of the Yoruba language, was found to be effective in ensuring effective health care before, during, and the follow-up care of patient-nurse service encounters at Adeoyo Teaching Hospital. It is suggested that linguistic orientation for better healthcare delivery should be mandated in the healthcare sector. Research on language preference during service encounters among nurses and their patient interaction in the hospital from the viewpoint of the patients is also suggested.