Current signing avatars are often described as unnatural as they cannot accurately reproduce all the subtleties of synchronized body behaviors of a human signer. In this paper, we propose a new dynamic approach for transitions between signs, focusing on mouthing animations for Portuguese Sign Language. Although native signers preferred animations with dynamic transitions, we did not find significant differences in comprehension and perceived naturalness scores. On the other hand, we show that including mouthing behaviors improved comprehension and perceived naturalness for novice sign language learners. Results have implications in computational linguistics, human-computer interaction, and synthetic animation of signing avatars.

翻译：当前手语虚拟角色常被描述为不自然，因为它们无法精确复现人类手语者同步肢体行为的所有细微之处。本文针对葡萄牙手语，提出了一种新的动态过渡方法，聚焦于口型动画。尽管母语手语者更偏好采用动态过渡的动画，但我们在理解度和感知自然度评分上未发现显著差异。另一方面，我们表明加入口型行为能提升手语初学者的理解度和感知自然度。研究结果对计算语言学、人机交互以及手语虚拟角色的合成动画具有启示意义。