One of my friends is doing Ph.D. in English on pragmatics, which focuses on speech act theory. Could you please suggest some good reading regarding this?
There are so many publications! I agree with Friedrich. A more focussed question would be nice.. Types of speech act? Speech acts in general? Indirectness in speech acts? Etc
If your friend wants to look into the topic from a developmental perspective, I would suggest Ninio and Snow's 1994 book "Pragmatic Development". It gives an excellent overview and presents data of children's pragmatic development.
Apart from special issues, there are four particularly prominent accounts of 'speech acts':
(1) JL Austin's 'How to Do Things with Words' (1975),
(2) JR Searle's 'Speech Acts' (1969),
(3) Bach & Harnish's 'Linguistic Communication and Speech Acts' (1979) and
(4) WP Alston's 'Illocutionary Acts and Sentence Meaning'.
The notions given of what an 'illocutionary act' (or 'speech Act') actually is differ strongly in each case: your friend should be aware of the possible fact that these authors are dealing with different phenomena. Thus, Austin is concerned with institutional act which involve (what he calls) the "securing of uptake"; in the case of Searle it is rather unclear what identity conditions the acts he deals with actually have; Bach and Harnish are dealing primarily with acts of communication ("communicative speech act"), and secondarily with institutional acts ("cnventional speech acts"), while Alston's interest is directed at acts of 'saying something' (in a somewhat pecular sense of 'saying' not equal to any of the beforementioned kinds of act). One of the important first decisions your friend shall have to make is thus: Which of the different conceptions of 'speech acts' does he/she intend to deal with in his/her diss?
[Note: Austin's and Searle's accounts are not easy to detangle; my own diss. 'Illocutionary Acts -- Austin's Account and What Searle Made Out of It' (2006) sets out to give detailed analyses of both. Searle's account was commonly recognised as the leading account for decades; during the eighties, Bach and Harnish's account became widely 'accepted', too. Most authors endorse the outstanding significance of Austin's work on the matter, but only few seems to have actually read the relevants texts authored by him (in any meaningful sense of 'read'); here the work of Marina Sbisà contains particularly helpful analyses.]
Apart from those already mentioned, Stephen Levinson's "Pragmatics" (1983) (Cambridge University Press) is still considered an excellent introcuction to Pragmatics in general and to speech act theory in particular.
If your friend is interested in a historical perspective, I recommend Andreas H. Jucker & Irma Taavitsainen (2008). Speech acts in the history of English.
Is it references that your friend needs or the actual texts? A basic search on the internet will provide some first rate articles with extensive references. But if you need the actual texts you have to look some more. I may be able to help with several of those.
To do research on speech act theory one should start by undestanding the original theory: Austin (how to do things with words) and Searle (Speech acts). From then on, there are too many references, particularly in English. I`d suggest your friend to narrow his question to a particular kind of speech act.
I suggest narrowing your friend's interest to a specific speech act. I think he has to consult Blum-Kulka's works ; Ting-Toomy's ; Leech's(2014); Trosborg's , and many others .