What is one class of speech acts described by J.L. Austin?
Descriptive fallacy:  Austin argued that performative utterances are not meaningfully evaluated as true or false but rather by other measures, which would hold that a statement such as "thank you" is not meant to describe a fact and to interpret it as such would be to commit the descriptive fallacy. J. L. Austin: John Langshaw "J. L." Austin (26 March 1911 – 8 February 1960) was a British philosopher of language and leading proponent of ordinary language philosophy, perhaps best known for developing the theory of speech acts.
performative utterances