Linguists have noticed that many swear words share the same sharp, punchy sounds—hard consonants like “k,” “t,” and “g” that burst out of the mouth rather than flow. When a study examined those sound ...

Made-up words like “clisious” and “smanious” are easier to remember when they sound beautiful. Could the feel of a word shape how we learn languages, sell products and even how languages evolve?

Corrected: An earlier version of this story incorrectly identified the tiers associated with challenging words. Children who enter kindergarten with a small vocabulary don’t get taught enough ...