In the myth of Pandora’s Box, Hermes gave Pandora the power of speech.
Hesiod’s account describes Pandora as assembled through the work of several gods. Hephaestus forms her, Athena teaches or clothes her, and other deities provide qualities that make her attractive and persuasive. Hermes contributes a mind and a voice, including the capacity for speech in common translations.
Hermes is the messenger of the Greek gods, so assigning him a role connected with language and communication fits his wider mythology. He is also associated with persuasion, cleverness, travel, trade, and boundary-crossing. His part in Pandora’s creation is therefore more specific than simply being the deity who delivers her.
Different translations phrase the gift differently, sometimes referring to speech, a voice, or a deceptive mind. The wording varies, but Hermes is the named god connected with Pandora’s speech in the relevant passage. This is separate from the existing question about which god gave her a deceptive mind.