The average adult knows approximately 12,000 to 35,000 words of his/her native language (depending on level of education). That includes all the words he/she regularly uses (active vocabulary), and all those he/she might never use, but understands the meaning of (passive vocabulary) should someone slip one into a conversation, e.g., “vouchsafe”… does anyone actually ever say vouchsafe these days? I heard my grandfather use it once, but he was 200 years old and people spoke like that back in Dickens’ day. And, of course, if you speak any other languages, your knowledge of words will be even greater than those numbers mention at the top of this item. All of the words you know are inside your head, and it’s long fascinated linguists as to where exactly they are located. Is a certain part of your brain a dictionary? Is there a chunk of your gray matter that functions as a lexical database? It turns out (see the above video), and what has always been expected by linguists, that meaning came first, and as you pick up the words to denote each meaning, that’s where the word is. Your head is quite simply full of words.