Final answer:
The common motif in the provided texts is characters' inability to speak, representing themes like powerlessness and transformation. Echo's myth and other narratives show how a muted voice can symbolize control or emotional states.
Step-by-step explanation:
The excerpts provided highlight various narratives in which the characters are either literally or figuratively unable to speak. This motif is a common literary device that can signify a range of themes, including powerlessness, oppression, or transformation. For example, the myth of Echo depicts her inability to speak except to repeat what has been said to her, showcasing the loss of her power and voice due to Hera's curse.
Similarly, in other narratives, characters experience moments where they cannot express themselves due to fear, societal constraints, or supernatural forces. These instances of muted voices often serve a symbolic purpose, reflecting inner turmoil, external control, or significant emotional states. The recurrences of such themes across different texts underscore the power of voice and the consequences when it is stifled.