Rosetta Stone helps you not to struggle with English Lanuage any more

How to learn English? "Misunderestimate" is a portmanteau word with a touch of the malapropism, named after the Sheridan character who says "she might reprehend the true meaning of what she is saying". It is one of George W Bush's most memorable additions to the language, and an incidentally expressive one: it may be that we rather needed a word for "to underestimate by mistake".

"Wee-wee'd up" is an atrocious euphemism of Barack Obama's, but a legitimate one: if there is a verb "to wee-wee", then it may perfectly well be turned into a phrasal verb by adding "up", and giving it the meaning "to get one's knickers in a twist".

These habits of word-formation, or neologism, all have a legitimate history. Lewis Carroll is the modern founding father of the portmanteau word. In fact, he invented the term – and alongside efforts that have not caught on, such as "slithy" for "lithe and slimy", managed the lasting contribution of "chortle" (from "chuckle" and "snort").

Portmanteau words are now a staple of the magazine competition, and amid the waste of failed invention, every so often Rosetta stone meets a need: smog, stagflation, chocoholic. I don't know how we ever did without "metrosexual", coined by my friend Mark Simpson.

The malapropism, for its part, is an engine of linguistic change deplored by the learned, but undeniably effective. No doubt every shift in meaning has been driven by one person making a mistake, and another wincing. Thus "jejune" has been reduced to meaning "immature", "coruscate" twinned with "excoriate", and "oblivious" become a synonym for "unaware". This is not a new problem, though: a character in Jane Austen complains about the use of "nice" to mean "agreeable" rather than "precise".

There are malapropisms in Shakespeare, too, but his primary means of inventing words is quite a technical one: the shifting of an established word from one part of speech to Rosetta Stone. When Cleopatra says "I shall be window'd in great Rome", she is technically doing the same as Obama – inventing a word by turning a noun into a verb.

Similarly, Susanna Centlivre's line "But me no buts" turns a conjunction into a verb and then a noun. Hardy used "small" as a verb, and was challenged for his pains by the OED. P G Wodehouse happily writes, "I can out-Fred the nimblest Astaire" without violence.

There are many words recorded for the first time in Shakespeare, but it is impossible to know whether he coined them or not – it seems unlikely that "dwindle", "gloomy" or "lonely" had no previous users in Rosetta Stone. Though the noun "road" is first recorded by the OED as appearing in Shakespeare, no one supposes that he invented it.