"I accept that sometimes American phrases have a vigour and vivacity. A relative of mine told me recently he went to a business meeting chaired by a Californian woman who wanted everyone to speak frankly. It was 'open kimono'. How's that for a vivid expression?" The BBC explores Americanisms, but they're not the first: The Telegraph, Daily Mail, and the Economist have also weighed in on the debate. (Somewhat previously.)
A Dictionary of Amercanisms by John Russell Bartlett, published 1848. A "vocabulary of the colloquial language of the United States" during the mid-19th century. As noted by jmorrison at the nonist (the source for this link), it is interesting to see much of what we find so common today " called out as 'americanisms' not yet included in the dictionary." The site has other goodies too, such as The Slave's Friend, a Christian anti-slavery tract, and Memoirs of a Captivity Among the Indians of North America, by John Dunn Hunter, published in 1823 and 1824 and recounting his life after being captured as a young boy and raised by Native American tribes. It provides an intimate, inside look at their societies, customs and battles.