All people= This means all the people in the world. This is used mainly in old-fashioned literary texts (such as the Bible) and formal speeches. It isn't used much nowadays in everyday English. All of people= This is incorrect All the people/ All of the people = These have a similar meaning. They refer to everyone in a specific group, for example 'All the people who bought this product are entitled to a refund.' ............................... I've never heard this before = You can say this to refer to a song or piece of music, or a word or expression, for example. I've never heard of this before = This means 'I didn't know that this thing existed'. It means that I have never heard anyone talking about this before, or never read anything about this thing.