Low Key Laughing. Like when you and perhaps your boyfriend or girlfriend are arguing and they saysomething dumb or funny. You let them know that you laughed buy you're still mad by saying lkl.
lkl was created from pure laziness to change lkl to lol.
International usage:
"That was so funny lkl!"
Meaning
That was so funny I laughed krazy loud!
Other Country interpretations
South Africa "That was so funny lkl!"
Meaning
That was so funny I laughed kak loud!
'Kak' creates emphasis in a sentence to highlight the laugh is even funnier to the user.