Thanks to Steven Schwartzman of wordconnections.wordpress.com for explaining that when English words have their origin in Greek words with consonant blends that don’t occur in English, like the pt- in helicopter, we tend to break them up incorrectly. For example, we guess that the morphemes (units of meaning) are heli-copter instead of helico-pter.
He gives two more examples. Amnesia is not am-nesia, but comes from a-, ‘not’ and mnesia, ‘remembering’ and pregnant is not preg-nant, but comes from pre-, ‘before’ and gnant, ‘giving birth.’
Amnesia reminds me of mnemonic, a memory aid like, “My very educated mother just served us nine pies,” which used to help students memorize the order of the planets from the sun – until Pluto was demoted. Now we need a new mnemonic for the planets. Anyone?
And we’ve always needed a mnemonic to help us remember how to spell mnemonic. Well, the way to remember that mnemonic starts with mn- is to think of amnesia, the word for not remembering. That’s right: not remembering can help you remember the memory device. Or something like that.