A derivation just means running words through the rules using a certain format (for more explanation, see our textbook pp. 98–99 or the partial answers for section handout 5.5). The following video demonstrates derivations by running ‘Patty’, ‘cat’ and ‘beauty’ through two phonological rules of English previously discussed in lecture.
A word of explanation: The UR (Underlying Representation) in the top tier is what speakers memorize in their mental lexicon, and PR (Phonetic Representation) in the bottom tier is what people actually say. The lines in between show the output of each rule (Aspiration and Flapping in this case). If the rule doesn’t apply, i.e. doesn’t change anything, then there is just a dash like this —.
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