Many of these new words are slang and will probably sound old-fashioned in a few years. The one I've heard the most is “cray cray” (a shortening of crazy crazy), meaning really crazy. Another popular word is “soof”, an acronym for “Swear On Our Friendship” that is used to emphasize the speaker is telling the truth. “Salty” is a now used to describe someone who is bad-tempered or annoying.
I also hear young people calling their friends “fam” (short for family) instead of the well-known “bro” (short for brother.)
Many words were popularized by the media. The Oxford Dictionary chose “selfie”—a self portrait usually taken with a cell-phone camera—as their word of the year. Even Obama and Pople Francis were seen taking selfies. It beat out “twerk”, the sexy dance move where you squat and thrust you bottom up and down, made famous by Miley Cyrus at the MTV Awards.
Several new words this year were portmanteaus (combining two words into one new word.) The big tech trend for 2014 is predicted to be oversized smartphones or “phablets”—phone + tablet. Another new portmanteau is “glamping” (glamour + camping), which is camping with more comfortable accommodation and facilities.
Some new words have been created using traditional suffixes (letters added to the end of a word to create a new word.) “Bigorexia” is the obsession to become more muscular. And “nomophobia” was created from no-mobile-phone phobia to describe when a person is afraid of being out of cell phone contact. We can also use the related adjective “nomophobic” and the noun for a person with the condition, “nomophobe”.
Some “new” words are actually old words with a new meaning. “Fade-out” has traditionally meant the technique in film where an image or sound gradually disappears; today it can also mean when lovers or friends slowly stop meeting and communicating with each other. And “sketchy” has come to mean strange, suspicious, dangerous, or illegal in addition to its traditional meaning of lacking details.
The English language has a long history changing nouns into verbs (just read Shakespeare), and this has created new words such as “showrooming”—the practice of looking for a product in a shop before buying it on-line—and “astroturfing”—hiding an organized political or corporate campaign as a popular movement.
There were a couple of words for money that became popular in 2013. “Bitcoin” is a purely virtual currency, but now some stores accept bitcoins for purchases and there are even bitcoin ATMs. A word that's more likely slang is “guap”, used to mean a lot of money.
Listen for these words in 2014; I'm sure you'll be hearing them more and more.