During his presentation, he lost voice from nervousness.

lost 是动词 lose 的过去式，lose 的本意是"失去、丧失"。 voice 的意思是"声音"，指人说话或唱歌时发出的声音。 lose one's voice 是一个固定短语，指由于疾病、用嗓过度或紧张等原因暂时说不出话，即"失声"。