We used to use that phrase a lot in the '70's, back when I was trying to impress my hippie friends. It's probably not as cool to use it now, but many people still do and they aren't all aging hippies.
Actually, it would probably be more correct to use:
de ce que je ai vu (from what I've seen)
Je ai vu ça avant (I've seen this before)
"Cool", meant "good", and no longer just referred to the temperature. After a while the term "Bad" came to mean "good", as well. What's wrong with just saying something is "good"? It's not zippy enough - we need to use "awesome" or "fly" or "chill" or some other strange morphing of language.
Do you remember "Sniglets"? I loved sniglets, words that weren't in the dictionary but should've been. Morphing of two words to describe something. Nonsense words for totally comic value, and the '80s public loved them. Here's a couple of examples:
- profanitype, the special symbols and stars used by cartoonists to replace swear words (*^&#...)
- pupkus, the moist residue left on a window after a dog presses its nose to it (my personal fave)
- askhole (someone who asks very annoying questions)
- bozone (the layer of air surrounding a stupid person)
As writers we enjoy the use of words and generally get irritated at the miss use of them. You've heard the term "Grammar Nazi"? I'm not one of those, because I face translations or writing from non English (as their first language) speakers every day and sometimes have to puzzle out what they really want to say. It can be challenging to make their messages completely understood. We writers want our words to tell a story, convey a feeling, entertain, frighten, but most of all - we want to express ourselves.
One of my favorite quotes is from James Michener, who says: "Writing, I love the swing and swirl of words as they tangle with human emotions."
Nice, isn't it? Enjoy the journey my writing friends, and don't be afraid to have some fun doing it.