Language is often implicated in humor. Humor may play off of lexical ambiguity (as in puns), or make use of linguistic ill-formedness or stigmatized forms, dialect features, etc. (as in ridicule using mimicry), or may use linguistic arguments (that is, logically fallacious lines of reasoning whose apparent sense is derived from linguistic factors like ambiguity, metaphor, idioms, formal similarities) etc. Mimicry for humorous effect may make specific use of linguistic features characteristic of a dialect or of an individual's speech pattern, or may impose artificial or exaggerated intonation patterns or voice quality. Listeners who view the speech patterns of another as unusual or different may laugh at them. Grammatical errors or differences can be the focus of humorous expression.
Some observers think these facts militate against a moral theory of humor. Many people are likely to see plays on grammar as unrelated to any kind of moral system -- especially linguists, who often view language as an affectless intellectual system (no coincidence!). Language is often thought of as a purely cognitive system, and for this reason, puns and linguistic humor are often proposed as counterexamples to the present theory.
However, all people live in a strongly evaluative sociolinguistic environment. Rare is the non-prescriptive linguist that lacks emotional commitments to linguistic well-formedness. Linguistic issues are emotional ones in all societies. People may be quite offended if you point out that they use the historically long-established forms ``ain't'' or ``aks'', or that they ``drop their /g/'s''. Certainly the hue and cry following ex-Vice President Dan Quayle's performance at a grade-school spelling-bee demonstrates the affective attachments people have to linguistic propriety. Further, innumerable sociolinguistic studies have certainly shown that pronunciation differences can evoke strong evaluative responses in speakers (in the ``matched-guise'' experiments of Labov, 1966, and his many students), to such an extent that speakers are quite willing to judge a speaker's intelligence, prospects for employment and friendship, etc., on the basis of their pronunciation. Indeed, people frequently devalue one another because of purported linguistic misbehaviors, which are defined with respect to a system of opinions about the natural and proper order of language.
On these grounds, humor based on linguistic malformation is indeed consistentx with the present theory, since it is clear that a moral violation may be perceived to occur. People have moral opinions about language: they think it ought to be a certain way, and they care about it. Humor based on percieved malformations of language, therefore, is not a counterexample to a moral theory of humor.