Costermonger a secret language, a code which only other costermongers understood. In her book, "Shadows of the Workhouse", Jennifer Worth observed that "Costers... spoke to each other almost entirely in back slang; incomprensible to an outsider." Many costermongers also used "rhyming slang"; where any word can be substituted with another word that rhymes with it. Examples of rhyming slang include: "tin lids" or "dustpan lids" for "kids"; "jimmy grant" for "emigrant"; "apple and pears" for "stairs"; "rubbidy dub" for "pub" and "trouble and strife" for "wife". The selection of rhyming words often suggested a symbolic association. For example, a "sorrowful tale"
Apples and oranges example, apples and pears are compared in Danish, Dutch, German, Spanish, Swedish, Croatian, Czech, Romanian, Hungarian, Italian, Slovene, Luxembourgish, Serbian, and Turkish. In fact, in the Spanish-speaking world, a common idiom is "sumar peras con manzanas", that is, "to add pears and apples"; the same thing applies in Italian ("sommare le mele con le pere") and Romanian ("a aduna merele cu perele"). In Portuguese, the expression is "comparar laranjas com bananas" (compare orange to banana). In Czech, the idiom "míchat jablka s hruškami" literally means 'to mix apples and pears'. Some languages use completely different items, such as the Serbian