This study explores Cipher, an adaptive language learning game tailored for the under-resourced Irish language, aimed mainly at primary school students. By integrating text analysis techniques, Cipher dynamically adjusts its difficulty based on the player's language proficiency, offering a customised learning experience. The game's narrative involves decoding spells to access Irish myths and stories, combining language learning with cultural elements. Development involved collaboration with educators to align the game content with curriculum standards and incorporate culturally relevant materials. This paper outlines the game's development process, emphasising the use of text analysis for difficulty adjustment and the importance of engaging, educational gameplay. Preliminary results indicate that adaptive games like Cipher can enhance language learning by providing immersive, personalised experiences that maintain player motivation and engagement.