Casual usage of i-adjectives and ending particles


In Real casual japanese one may hear

> 明日のテストってこわ。。。

I am wondering, how often this level of 'casualness' happens.

Can I add sentence ending particles, even though there is an い omitted (and
です). For example:

> ゆきは走るのがはやね。

I omitted the whole structure, but still added ね to emphasize, that Yuki runs
fust, doesn't he?

However this is pretty standard, for a plain form, am I right?

> おもしろいね

If a similar question has been answered somewhere, please link it for me, and
also I'm not sure if my question is phrased correctly, I hope it's
understandable.




ゆきは走るのがはやね is impossible.

Those stand alone stems of i-adjective are not so much a casual form as a kind
of interjection you use when you are surprised and it doesn't allow any
grammatical elements to follow. In addition, it's different from collapse of
diphthongs.

