Background: South Africa's "Language-in-Education Policy" (LiEP) provides for bi/multilingual education, but schools are only supported to choose monolingual English language policies from Grade 4 and ignore the learners' home language or languages as resources for learning. Many teachers translanguage orally, using the learners' home language and English to make learning more meaningful but seldom extend this to written translanguaging. Objectives: Research was conducted to document the process and effects of a teacher development project, translanguaging-for-learning (L4L) which supported teachers in developing translanguaging pedagogies to improve learner access to the curriculum and to develop academic bi-literacy. Method: This article focuses on the development of one senior phase (Grades 7-9) natural science teacher who participated in the L4L project. Data were collected following an ethnographic approach in workshops and classrooms through observation, interviews, photos, videos, and learners' workbooks. Results: The research illustrates how with workshop engagement, mentoring support and the provision of multilingual dictionaries, a teacher's bi/multilingual languaging skills were legitimised and mobilised to engage learners in knowledge construction, both orally and in writing. Classroom interaction shifted from being teacher-led to being more learner-centred and bilingual, providing opportunities for biliteracy, and identity affirmation. Conclusion: The findings illustrate improved learning opportunities through planned, systematic translanguaging pedagogies. Contribution: The research suggests a model for bi/multilingual education and teacher development that recognises African languages as important resources for learning to further linguistic equity, access, and social justice.