Analysis of existing key layout models from the perspective of user adaptation

Context and Relevance. Standard keyboard layouts (QWERTY, Dvorak, Colemak), despite various optimization attempts, remain fixed and do not account for individual user characteristics. This limits ergonomic efficiency and reduces typing comfort and performance. Modern touchscreen interface technologies enable a shift from universal layouts to fully customizable keyboards tailored to users' physiological, cognitive, and professional needs. Objective. To justify the necessity of transitioning to the concept of a fully customizable touchscreen keyboard and to present a user-adaptive layout model based on ergonomic and functional criteria. Hypothesis. A personalized key layout, designed according to frequency analysis, biomechanical principles, and individual user preferences, improves typing speed and accuracy while reducing fatigue, compared to universal keyboard schemes. Methods and Materials. A comparative analysis of existing layouts was conducted in terms of finger load distribution, effort allocation, and frequent typing patterns. The concept of manual configuration for touchscreen keyboards was substantiated, incorporating metrics such as finger movement distance, hand alternation, professional context, and multi-profile adaptability. Results. The proposed approach to user-defined layout design enables interface adaptation to individual needs, reducing motor strain, balancing input workload, and enhancing ergonomic efficiency without relying on automated optimization methods. Conclusions. A touchscreen keyboard with manual layout customization offers a promising solution for personalized input interfaces. A system of criteria is proposed for designing and evaluating user-specific input schemes. Future work may include the development of a formalized layout construction methodology and cross-device portability formats.