It is important to co-exist with people of different national languages, and the use of digital signage has become widespread as a means of displaying multiple languages. In this paper, the authors propose a dual- language display method using oscillating animation for digital signage (bilingual oscillatory display; BOD) to solve the problem of conventional multilingual display method on digital signage. The proposed method improves the amount of information per area by inserting texts written in one language between lines of the text written in another language and maintains readability by providing two languages with independent animations that oscillate circularly. To explore the parameters of the most readable animation, the reading time and the subjective impression of readability were measured for BOD with various animation parameters. The result showed that the optimal amplitude is 0.0, 7.1 or 28.6% and the optimal oscillation cycle is 0.94, 1.25, 1.67 or 2.22 seconds.