Audio problem: When Karen is in the house talking on the phone, she says "He won't come down," (referring to Toshio) but her lips don't move.
Audio problem: After the detective listens to the message that Susan leaves for her brother on the answering machine, the detective pushes the button to locate the missing phone. The detective as well as another officer begin to follow the sound of the ringing phone which is very loud and audible near them. As they begin walking down the hallway towards the door the ringing becomes muffled and when he opens the door it becomes loud again.
Answer: Well, in the Japanese original (Ju-On: The Grudge), it shows that Takeo, the father, killed his wife by shoving a knife down her throat or something similar to that. When he was killing her, she tried to scream, except her scream came out all messed up (because the knife hit the vocal chords), which explains the horrible croaking noise. There's no doubt about it that it's the way she was killed in this version.