About two weeks ago, I was using a tape recorder, I didn't say much, just hello and a few different words. Nothing threatening or provoking. I reviewed the tape and after I finish talking, you can hear a voice, it definitely does not belong to anyone in the house. My family and I listened to it, and the only word that it sounds like is "past". The voice starts whispering and then it gets very loud and it sounds unfriendly. In between the first word and the moment the volume increases, I think there's some counting, but I'm not an expert, I don't know for sure. Another thing you should know is that previous to this, we've heard many unexplained noises. One in particular, my mom was downstairs and my grandma and I were upstairs and Grandma and I heard a agonized scream that came from downstairs. I ran to the edge of the stairs and yelled down to Mom. When she came upstairs, I asked her if she had heard anything, she said that she hadn't. There are some more incidents but those are the two major ones. But since then we haven't noticed as much activity but another family member has awoken in sleep paralysis.
Are we in any danger? If so, what can we do?

It doesn't sound like your in any danger at all except possible that of an over active imagination. Have you tried letting the recorder go again to see if any sounds appear? Also keep in mind that some electronics can pick up radio waves and you can't tell the difference between being off channel and a disembodied voice.

From what your saying there is nothing to fear.

There isn't anybody here that can say yes or no to whether your home is really haunted. For all we know this is just a case of over active imaginations. However, you are there and believe in what you experience.

If there is a spirit in your home, yes you could possibly be in danger. I subscribe to the idea that no spirit it harmless. In that case I would recommend you seek help from a local ministry.

Califdad makes a good point. Electronics DO pickup outside interference. I've experienced this myself and it can be quite startling. But doesn't prove there is a ghost there. Orbs and EVPs are about the worst thing anyone can use to offer as evidence for paranormal activity.

Was it a new tape that you were recording on? Or were you taping over something that was already there and heard some of it when you played it back?

Just a thought... was there a TV on in another room somewhere which was showing a film or similar,this would account for the scream maybe... especially if it had been left on with no one in the room which happens quite often in most houses.