Basic linguistic notions

locutionary act – producing a meaningful linguistic expression, uttering a sentence. If you have difficulty with actually forming the sounds and words to create a meaningful utterance (because you are a foreigner or tongue-tied) then you might fail to produce a locutionary act: it often happens when we learn a foreign language.

illocutionary act – we form an utterance with some kind of function on mind, with a definite communicative intention or illocutionary force. The notion of illocutionary force is basic for pragmatics.

perlocutionary act – the effect the utterance has on the hearer. Perlocutionary effect may be verbal or non-verbal. E.g. I’ve bought a car – Great! It’s cold here – and you close the window.

2. Classifications of speech acts. Indirect speech acts.
It was John Searle, who studied under J.Austin at Oxford, who proposed a detailed classification of speech acts. His speech act classification has had a great impact on linguistics. It includes five major classes of speech acts: declarations, representatives, expressives, directives and commissives:

Speech act type	Direction of fit	s – speaker, x - situation
Declarations E.g. I pronounce you man and wife. You’re fired.	words change the world	S causes X
Representatives E.g. It was a warm sunny day. John is a liar.	make words fit the world	S believes X
Expressives E.g. I’m really sorry. Happy birthday! (statements of pleasure, joy, sorrow, etc.)	make words fit the world	S feels X
Directives E.g. Don’t touch that (commands, orders, suggestions)	make the world fit words	S wants X
Commissives E.g. I’ll be back (promises, threats, pledges – what we intend to do)	make the world fit words	S intends X

J.Searle can also be merited for introducing a theory of indirect speech acts. Indirect speech acts are cases in which one speech act is performed indirectly, by way of performing another: Can you pass me the salt? Though the sentence is interrogative, it is conventionally used to mark a request – we cannot just answer “yes” or “no”. According to modern point of view such utterances contain two illocutionary forces, with one of them dominating.
Another classification of speech acts was introduced by G.Potcheptsov. It is based on purely linguistic principles. The main criterion for pragmatic classification of utterances is the way of expressing communicative intention. This classification includes six basic speech acts:
constatives, promissives, menacives, performatives, directives and questions. More details can be found in the book by И.П.Иванова, В.В.Бурлакова, Г.Г.Почепцов “Теоретическая грамматика современного английского языка”, С.267-281.