"Lannie" sounds like a some sort of diminutive or nickname. It could be a pet name for "
Alanna" (an Irish term of endearment meaning, "my child") or "
Alana" (feminine form of the name "
Alan") or even a pet name for "
Elaine" (a form of "
Helen" meaning "light").
I dunno, I'm just guessing here. Most American names ending in "ie" tend to be diminutives.
-- Nanaea