I am wondering if there is a term for sentences that describe what the sentence accomplishes. For example, the phrase "I'm warning you." The sentence simultaneously does the warning and says it is warning.
They are performative utterances (sentences which do something in the world, rather than describing something about it). A few more examples...
- I do (take this woman to be my lawful wedded wife) - in a marriage ceremony.
- I name this ship the "Queen Elizabeth"
- I give and bequeath my watch to my brother - in a will
- I promise (anything, in the right context)
In something like This sentence contains five words, I suppose you could say that what the sentence does is introduce itself into the world, so it can be analysed (by itself, as it happens).
This could be considered a type of meta-sentence, or self-referential sentence.
The archetype would be:
This is a sentence.
or similar contrivances such as:
In this sentence the letter 'e' appears ten times.
In ‘The Study of Language', George Yule writes:
We use the term speech act to describe actions such as ‘requesting’, ‘commanding’, ‘questioning’ or ‘informing’. We can define a speech act as the action performed by a speaker with an utterance.