1. the quality or state of lacking tone, expression, or emotional inflection in speech or sound

Examples

• The robot’s tonelessness made it difficult to understand the intended meaning.
• Her voice had a strange tonelessness that made everyone uncomfortable.
• The announcement was delivered with complete tonelessness.
• The tonelessness of his speech suggested he was reading from a script.
• The computer’s tonelessness contrasted sharply with human conversation.
• She spoke with such tonelessness that no one could tell if she was joking.