Here is a fun word to say. I have heard the words many times before, but now that I am starting to write more, especially since I want to branch into poetry, I looked the word up so I could be sure I knew exactly what it meant. And how to pronounce it. Mary Oliver writes about diphthongs in A Poetry Handbook.

Diphthong – (pronounced dif-thong) an unsegmentable, gliding speech sound varying continuously in phonetic quality but considered to be a single sound or phoneme, as the oi sound of toy or boil.

Usage: “The initial four lines are rife with w‘s and th‘s; f is there, and v. Three sets of double ll‘s. The heaviness of the vowels is increased by the use of diphthongs. The two words that end with a mute (think and up) are set within the lines and thus are softened. All other mutes are softened within the words themselves. One could scarcely read these lines in any other than a quiet, musing, almost whispered way.”

Mary Oliver is speaking of the first stanza of Robert Frost’s poem “Stopping by Woods on a Snowy Evening”:

Whose woods these are I think I know.
His house is in the village though;
He will not see me stopping here
To watch his woods fill up with snow.