After Kagome fires Kikyo's sacred arrow at the loose shard, and Kikyo's image is overlaid on Kagome's, when Kagome screams "Go", her voice is much deeper than usual, more similar to Kikyo's. It's an audio counterpart to the fact that they overlaid Kikyo's image on Kagome's.
Sesshomaru: Naraku.
Naraku: Hmm?
Sesshomaru: Is that all you have to say to me? You seem to think that I would hold back my sword for the sake of humans -- I'm not nearly so sentimental.
Jaken: Ohh I knew it!