To be at a loss as to what is being said; to speak or write in an incoherent manner.
他在会议上的发言逻辑混乱，让人完全不知所言。
His speech at the meeting was so illogical that it left everyone completely at a loss as to what he was talking about.
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To be at a loss as to what is being said; to speak or write in an incoherent manner.