A world with roman numeral alphabet

Tomorrow you will wake up and all the letters will be replaced by roman numbers. That'll be "ok" when you'll learn the replacement's order!

Nevertheless, today you have the possibility to make it a dream if you are able to translate That won't happen thanks the two following sentences:

XXIV-VI-III III-XI-IV-V-XVI?
Bye Earth?

XII-XIX-III-III-X II-III-XIX-XIX, XII-XIX-III-III-X V-VIII-XV-XVI-V!
Sleep well, sleep tight!


numbers are assigned based on position on a QWERTY keyboard. E is III because it is the third character in the first row, R is IV, T is V, Y is VI, and so on.
So, That won't happen translates as:
VI-XVI-XI-VI II-IX-XXV-VI XVI-XI-X-X-III-XXV