Sign Language Interpreter: A Mobile-Based Communication Application for Bridging the Communication Gap Between Deaf and Hearing Individuals

Sign Language Recognition; Mobile Application; Mediapipe; Text-To-Speech; Assistive Technology; Android; ISO/IEC 25010

Authors

  • Felise O. Marcaida School of Science and Technology, Centro Escolar University – Manila, Philippines
  • Althea D. L. Romero School of Science and Technology, Centro Escolar University – Manila, Philippines
  • Robert John V. Santos School of Science and Technology, Centro Escolar University – Manila, Philippines
  • Eliza Ayo School of Science and Technology, Centro Escolar University – Manila, Philippines
May 20, 2026

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Communication between deaf and hearing individuals remains a persistent challenge despite advances in mobile and machine-learning technologies. Existing sign language interpretation tools often suffer from limited vocabulary, dependence on specialized hardware, lack of integrated text-to-speech (TTS) functionality, environmental sensitivity, and the absence of offline capability.

This study aimed to design, develop, and evaluate a mobile-based Android application capable of (a) translating American Sign Language (ASL) gestures into text and synthesized speech in real time, (b) providing a built-in tutorial of the alphabet and commonly used words, and (c) operating offline on standard Android smartphones.

A descriptive-developmental research design was employed, complemented by an Agile software development life cycle (Define–Design–Develop–Demonstrate–Release). The application was implemented in Java using Android Studio, with hand-landmark detection performed by Google's MediaPipe framework. Quality assurance was conducted through automated tools (Sauce Labs, BrowserStack, WeTest, SonarQube) covering functionality, usability, performance, security, compatibility, reliability, and maintainability. Manual testing examined the influence of lighting, background, hand position, and hand size. User Acceptance Testing (UAT) was administered to 30 purposively sampled respondents (15 deaf, 15 hearing). Data were analyzed using percentages, weighted mean, and standard deviation.

Functionality testing yielded a 90.0% pass rate. Security testing revealed no high- or medium-risk vulnerabilities. Compatibility testing confirmed seamless operation on Android 12, 13, and 14 (rated Excellent) and acceptable performance on Android 11 (rated Good). Recognition accuracy was approximately 75% under controlled conditions, with optimal performance observed in natural light, against solid backgrounds, and with the hand placed frontally to the camera. UAT results across the eight ISO/IEC 25010 quality characteristics (Functional Suitability, Performance Efficiency, Compatibility, Usability, Reliability, Security, Maintainability, and Portability) ranged from 4.55 to 4.72 on a 4-point scale, all corresponding to a "Strongly Agree" verbal interpretation.

The developed mobile application addresses key gaps identified in prior literature by integrating real-time gesture-to-text translation, on-device text-to-speech synthesis, an embedded tutorial, and offline functionality on standard Android hardware. While the system performs reliably under controlled conditions, future work should focus on expanding the lexicon, accommodating dynamic gestures, improving robustness to lighting and background variability, and supporting cross-platform deployment.