What relative weighting should be given to court case, to psycholinguistic and sociolinguistic explanations of an alleged offence? We review the case of an African-American plaintiff, who claimed that her receipt of work of a framed document with the title "Temporary Coon Ass Certificate" from a white mailer supervisory-level employee in the same agency constituted racial discrimination in the workplace. Dialect research conducted by JJS, as expert witness for the prosecution, demonstrated that the dialectical use of coon ass to refer to Cajuns (white settlers of French descent) was restricted to the states of Louisiana and south-eastern Texas. It was argued by the prosecution to be unreasonable to expect someone from another part of the USA to know the meaning of the word. The jury found in favour of the plaintiff. The prosecution case rested upon the premise that when a word is unknown, it will be interpreted by breaking it down into smaller units, in this case coon and ass, both derogatory terms, the former strongly racist. We explore the psycholinguistic rationale for this assumption and its converse, that when a word is well known to an individual (s)he may fail to see how it is constructed.