This study explores the educational outcomes of Cipher, a Digital Game-Based Language Learning (DGBLL) application, focusing on vocabulary acquisition in Irish language learning. Cipher integrates engaging game mechanics with pedagogical principles, with the aim of enhancing Irish learners’ language skills. Using a double-baseline model, we assess learning gains among 45 primary school students. Results show vocabulary improvements in the experimental groups compared to the control group, underscoring Cipher’s educational potential. Key factors contributing to its success include a pedagogical focus, cultural responsiveness, curriculum alignment, content co-creation and innovative game design. This study highlights the potential of DGBLL applications like Cipher to support language acquisition, particularly in less commonly taught languages.