Talking with a "straight tongue" in the context of Chief Joseph's speech refers to speaking honestly, truthfully, and without deception. It symbolizes integrity, sincerity, and a commitment to open and transparent communication. Chief Joseph used this phrase to emphasize the importance of trust and understanding between different cultures and peoples. By speaking with a straight tongue, he intended to convey his genuine intentions, his desire for peaceful coexistence, and his willingness to engage in respectful dialogue.