As communications are increasingly taking place virtually, the ability to present well online is becoming an indispensable skill. Online speakers are facing unique challenges in engaging with remote audiences. However, there has been a lack of evidence-based analytical systems for people to comprehensively evaluate online speeches and further discover possibilities for improvement. This paper introduces SpeechMirror, a visual analytics system facilitating reflection on a speech based on insights from a collection of online speeches. The system estimates the impact of different speech techniques on effectiveness and applies them to a speech to give users awareness of the performance of speech techniques. A similarity recommendation approach based on speech factors or script content supports guided exploration to expand knowledge of presentation evidence and accelerate the discovery of speech delivery possibilities. SpeechMirror provides intuitive visualizations and interactions for users to understand speech factors. Among them, SpeechTwin, a novel multimodal visual summary of speech, supports rapid understanding of critical speech factors and comparison of different speech samples, and SpeechPlayer augments the speech video by integrating visualization of the speaker's body language with interaction, for focused analysis. The system utilizes visualizations suited to the distinct nature of different speech factors for user comprehension. The proposed system and visualization techniques were evaluated with domain experts and amateurs, demonstrating usability for users with low visualization literacy and its efficacy in assisting users to develop insights for potential improvement.

翻译：随着交流日益虚拟化，在线演讲能力正成为一项不可或缺的技能。演讲者在吸引远程观众方面面临独特挑战。然而，目前仍缺乏基于证据的分析系统，帮助人们全面评估在线演讲并进一步发现改进可能性。本文介绍SpeechMirror——一个基于多场在线演讲洞察、促进演讲反思的可视化分析系统。该系统评估不同演讲技巧对有效性的影响，并将其应用于具体演讲，使用户感知演讲技巧的表现效果。基于演讲因素或脚本内容的相似性推荐方法支持引导式探索，以扩展演讲证据知识并加速发现演讲表达可能性。SpeechMirror提供直观的可视化与交互方式，帮助用户理解演讲因素。其中，新型多模态演讲摘要可视化方法SpeechTwin支持快速理解关键演讲因素及比较不同演讲样本；而SpeechPlayer通过将演讲者肢体语言可视化与交互集成到演讲视频中，支持聚焦分析。系统采用适配不同演讲因素独特性质的可视化方式，便于用户理解。经领域专家与业余爱好者评估，该可视化系统对可视化素养较低的用户同样具有可用性，并能有效辅助用户形成潜在改进洞见。