Dogs and cats populate our language in clever and creative ways.

When I was growing up, I was a shy, quiet child, and the phrase I heard most often from my grandmother was "What's the matter? Cat got your tongue?"

While it seems as if this saying should have a colorful history, its origins are as shy as I was. Its first known appearance in print was in Ballou's Monthly Magazine, Vol. 53, in 1881, where it was described as a phrase said by children. One other theory, unsupported by quality references, suggests that the saying dates to the Middle Ages, when it was thought that a witch's cat would steal or control the tongue of anyone who saw the witch in action so that she couldn't be reported to authorities.

This time of year is notable for its "dog days," known for their scorching heat. The dog days occur in summer when Sirius, the dog star, shines brightly in the sky. Its name derives from the ancient Greek word "seirios," meaning "sparking," "fiery" or "burning." The star, which rises early in the morning in the path of the sun, was thought to be the cause of hot midsummer days. The dog days begin in mid-to-late July and end on Aug. 11.

The Cambridge Dictionary defines a "cool cat" as a fashionable person. I prefer the American Heritage Dictionary's slang definition of the word cool — composure or poise — because that so perfectly describes a cat's normal state of being.

The phrase "cool cat" entered the language in the 1940s, associated with jazz music. The digital Oxford English Dictionary says slang references to cats as people who appreciate jazz date to 1936, and the use of cool in reference to jazz music appeared in 1947. The mashup "cool cat" probably occurred soon thereafter.

The metaphor "black dog" as a term for depression has a long history. The negative image of black dogs dates to Roman times, when the poet Horace wrote that the sight of a black dog with puppies was a bad omen. Wordsmith Samuel Johnson used the phrase in the 18th century to describe his melancholia, and Brewer's Dictionary of Phrase and Fable listed the saying "a black dog has walked over him" to describe a sullen person. In the 20th century, British Prime Minister Winston Churchill used the phrase "black dog" to refer to his own depression.

Have you ever let the cat out of the bag? This idiom, referring to spilling a secret, has no clear origin, but Barbara Mikkelson of the urban folklore website Snopes.com wrote in 2012 that "it could have to do with a similarity between the behavior of both secrets and cats — once either is let out, they go wherever they want."

I am reminded of the time our late cat Peter the Gray trapped himself inside a plastic bag and ran frantically back and forth down the hall trying to escape it. In much the same way, a secret-keeper often struggles to contain his or her knowledge until it finally bursts out — the way Peter did from the bag.

It's a dog's life. We all wish we could live that, don't we? Or do we? What does that phrase mean? In its earliest known reference in a 16th-century manuscript, it referred to a miserably unhappy existence. But considering the multibillion-dollar pet industry in this country alone, I think that now we can safely say that the phrase refers to a pampered life indeed.