Question

Many catchy phrases and some new words come into American English by way of _____.

Answer 1

Many catchy phrases and some new words come into American English by way of advertising.

A catchphrase is a phrase or expression recognized by its repeated utterance. Such phrases emerge in popular culture and in the arts, and is usually spread through word of mouth and a wide range of mass media including films, internet, literature and publishing, television and radio.

Some American catchy phrases include:

"Bernie, the bolt!"

"Ooh, you are awful ... but I like you!"

"Don't panic!"

Answer 2

The answer is advertising, as commercials tend to use these catchy phrases  to attract the potential buyers of the product, so that they will remember and use the slogan.