"TTYL" can be spelled "ttyl" in all lowercase. Both uppercase and lowercase versions mean the same thing, and are perfectly acceptable. Just be careful not to type entire sentences in uppercase, lest you be accused of shouting online.
Example of TTYL usage:
- (User 1) Gotta go, boss is coming.
- (User 2) kk, ttyl.
Another example of TTYL usage:
- (User 1, instant message) Sec, telephone ringing...
- (User 2) ok, no worries.
- (User 1) OK, I'm back. That was my kid, I need to pick her up from school right now. I guess she forgot her bus pass at home.
- (User 2) no worries, TTYL!
The TTYL expression, like many cultural curiousities of the Internet, is a part of modern English communication.
Read more Internet abbreviations and shorthand expressions...