Fix spelling error concatinated -> concatenated
Correct form of string concatenation.
Mention print is a language construct
Move reference operator to site next to variable, as per docs
Add description of typecasting
Make if statement result clearer
Make comparisons clearer when type juggling
Add example of currying
Clarify anonymous functions as callbacks as arguments
Replace tabs with spaces
Correct syntax error declaring final method
Use sinlge line breaks for clarity