He used riddling to talk to Smaug I think because he wanted to stall and waste time as he figured out a plan. He also used riddles to talk to Golem who he clearly was trying to stall to save himself as Golem wanted to kill and eat Bilbo. So it is a reoccurring theme of Bilbo and it makes sense.
A critical listener only takes in what's thought as important points, where as an appreciative listener is more likely to take it all in and enjoy every little bit.
A morpheme added at the end of a word to form a derivation
append, especially as a suffix.
