See also: String.
A string literal is not a variable. A string literal is a series of alpha-numeric characters encapsulated within quotes (single or double). String literals are have many purposes in programming.
"This is a string literal"
'This is a string literal'
Quotes may be used inside of string literals. For example:
'This is a "string literal"'
"This is a ""string literal"""
The double quotes used in the example above evaluate to a single " in the value returned.