Hallelujah is also sometimes considered halleluyah, because thats how its pronounced, and because God's names are "Jahova" or short form "Jah", or "Yahwah", or a short form "Yah", which composes the ending of the word.
Hallelujah is the Greek mode of spelling the Hebrew words, which are translated "Praise Ye Jehovah." Notice Hallelu"jah" ends with Jah. Jah is a shortened form of Jehovah.
Most people have no idea that when they say Hallelujah they are actually saying "Praise Jehovah," the name for the Hebrew, Muslim, Christian God. Hallelujah appears in the Christian Greek scriptures and is a good example that first-century Christians used the divine name.
God walked up to them and said, "Ok. Go on, praise me then." The guys started...
Guy1: God, you're so cool
Guy2: God, you're so amazingly funny.
Guy1: Yeah. I love your sense of humor.
Guy2: Not to mention how nice you look.
Guy1: Like really man. What a crazyass haircut.
Guy2: I wish I was like you, God.
God: That's so sweet! Thanks guys.