CanTONEse, a self-learning mobile app for Cantonese tones, was designed to support the learning of non-local students in Chinese Language Proficiency Courses. Teaching materials with recordings, self-assessment exercises, an interactive game and daily conversations are available in the app. One distinguishing feature of the app is the visualisation of tones. Throughout the app, tones are (1) colour-coded, (2) represented by movements of animals according to pitch heights and contours, and (3) drawn on a music score sheet, enabling a concrete and intuitive representation of tones. Another prominent feature is interactive learning with multimedia materials. Interactive functions including (a) recording function, (b) a tone-shape game and (c) five video clips of daily conversations are provided to improve tone production and perception. With the app, the students' learning of Chinese could be facilitated outside classrooms. The app has been introduced to non-local students of CHLT 1102 Elementary University Chinese I, CHLT 1202 Elementary University Chinese II and CHLT 1104 Elementary Self-Learning Chinese in the 2019-20 academic year. Together with a detailed explanation on the design of the app, various functions will be demonstrated, as well as showing how the app contributes to Chinese Language Proficiency Courses. A further step is to promote the app to different teaching units in CUHK, and it would be our pleasure to receive comments from experts.