Adding new words and phrases into English has been greatly enhanced by the pleasure we get from playing with words. There are numerous alliterative and rhyming idioms which are a significant feature of our language. We start in the nursery with choo-choos, move on in adult life to hanky-panky and end up in the nursing home having a sing-song.
The repeating of parts of words to make new forms is called reduplication. There are various categories of this: rhyming, exact and ablaut (vowel substitution). Examples, are respectively, okey-dokey, wee-wee, and zig-zag. The words that make up these reduplicated idioms often have little meaning in themselves and only appear as part of a pair. In other cases, one word will allude to some existing meaning and the other half of the pair is added for effect or emphasis. Is there anything other than a spider that is eency-weency? Is there anything other than a dance that is hokey-pokey?
During the 1920s, following the First World War, when many nonsense word pairs were coined, such as the bee's knees, heebie-jeebies etc. Willy-nilly is over a thousand years old. Riff-raff dates from the 1400s and helter-skelter, arsy-versy ( a form of vice-versa), and hocus-pocus all date from the 16th century. Now we have bling-bling, boob-tube and hip-hop. Just thought I would razzle-dazzle you with this one.