Silence.

If words didn't exist. How could you say that you loved someone the easiest way? Is it with a handshake? Or a simple touch on the back? I personally believe that the words "I love you" is the most powerful words in the world. Not because it demonstrates a persons feelings, it's because it's so much feelings involved in it. When you hear the words "i love you" you immediatly get this warm and cozy feeling inside of you. You can't really describe the feeling, you can just say how good it feels. So how would you decide how to say i love you without words? i mean, you can't technically argue and discuss how to, because there is no words.
I think that the easiest way to say i love you in a world that never have had a single word in their mouths would be a gentle rub on their cheek and a little kiss after. The gentle rub is like a question, "can i love you?" if the woman or man rejects it's clearly a no. But if she or he doesn't, it's good to go. Everything would be so freaking awesome if this world would be a silent one. The technology had been so cool. Imagine being a teacher in a world without words. How would that be?