The coinage of 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 the language. These aren't restricted to poets and Cockneys; everyone uses them. 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.
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