Words are merely sounds until they become associated with an object or an action or a feeling.
And the way sounds come to have meaning is through repetitive exposure to spoken language in context of a relationship. An infant who heard spoken words only from a radio would never really come to understand language. As soon as the infant makes the connection between the object and the sounds, then those sounds become a word. That's how meaning comes to words, by making the association between the sound and the object. In the beginnings of our lives, however, sounds become words through repetitive opportunities of experiencing the parent, teacher, or caregiver making the connection between the sound and an object, or the sound and a behavior, or the sound and a feeling.