The word "Champer" is a rarely used term in English language. It is not present in major dictionaries, but it is sometimes found in informal speech. Its spelling is a good example of why the International Phonetic Alphabet (IPA) is useful for learners of English. In IPA, "Champer" would be transcribed as /ˈtʃæmpər/. This shows that the "ch" is pronounced as /tʃ/, the "a" sound is represented by /æ/, and the "er" is pronounced as /ər/. Remembering these phonetic symbols can help learners spell and pronounce unfamiliar words more accurately.
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Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.