Buffy did not understand what the woman was trying to say but she did understand the motioning movement so began to walk with her wondering where they were going. Then she said her name, or at least Buffy interpreted that as what she'd been doing and did the same.

She pointed to her own chest and said "Buffy." Then she pointed to her and said, "Constance." Just in case she hadn't been saying her name, that would give her a clue that that was how Buffy had understood her to say.