First Time Viewer

Yes, most Italian horror of that era was done this way. The actors do their lines, but they are dubbed over in English. They may or may not have been spoken in English originally (it was obvious the old woman at the end was not speaking the same lines that you heard.) I don't know why they did this, though.

It's actually common industry-wide for young boys to be voiced by women (in animation, etc.) because of the pitch. This one was done poorly though, it was one step away from the Monty Python guys playing old women.

Filmmakers and producers would sometimes get a woman to voice the part of a child because it was more expensive to pay an actual child actor to do a job like that. Plus there are strict rules and regulations about when children are allowed to work, and filmmakers usually want to avoid that if at all possible.

You should try watching "Burial Ground" if you've never seen that. There's a character who is supposed to be a young boy, is played by a small adult man, and is voiced by a woman.