A “hypocorism” is a pet name or familiar name. “Jimmy” for “James” or “Betty” for “Elizabeth.” “Hypocorism” probably needs a pet name of its own. It’s one of the rarest words in English (and that’s saying something). It was included in the 1899 edition of the OED, and classified as “rare” even then. The OED, of course, insists upon at least one recorded use of a word, and that’s exactly what they had for “hypocorism;” it first appeared, once, in 1850.
“Hypocorism” comes from Greek, and its literal meaning is “somewhat childlike”.
Even though “hypocorism” is an extremely rare word, and one you won’t find in most modern dictionaries (including the current OED, which gave up on it entirely sometime in the past century), you might encounter it in reference books about names. Apparently there are people who study these things, and they know that the most common “hypocoristic adaptations” of names involve simply reducing a name to its first syllable. “Benjamin” becomes “Ben,” for example. Another less common shortening involves also dropping a letter or two, so the hypocoristic adaptation of “Frances” might be (if you visit the 19th century) “Fan,” or, if you’ve misplaced your time machine, “Fannie.”
Hypocorisms aside, there are some interesting notes about changes in the pronunciation of names over the years. “Thomas”, for example, was originally pronounced with a soft “th” sound at the beginning rather than today’s “t.” “Anthony” went the other way; it was originally “Antony” without the “h,” and pronounced that way. Apparently the pronunciation with “th” in the middle is a development that mostly occurred in the US, and the spelling changed along with it.
Other hypcoristic oddities are that “Ned” is an adaptation of “Edward” and “Nan” of “Anne.” That leading “n” seems to have come from the practice, common about three centuries ago, to use the word “mine” to refer to someone close. So “mine Frank” or “mine Sally” would be what you’d call, for example, a family member. “Mine” was gradually reduced to “my,” and in the process “mine Ed” and “mine Ann” became reduced to “my Ned” and “my Nan.” Eventually “Ned” and “Nan” were all that remained.
Finally, some hypocorisms come from adults imitating babies. “Buffy” is a hypocorism for “Elizabeth” because babies sometimes come up with “Elizabeff” when learning language. That’s also where the less common “Lilibet” arose, but in that case the derivation was vouched for by none other than Queen Elizabeth herself! But I bet she didn’t know the word “hypocorism.” (On the other hand, kings need to know the terminal velocity of unladen European and African sparrows, so maybe she did.)
