As described above, ESP has had a relatively long time to mature and so we would expect the ESP community to have a clear idea about what ESP means. Strangely, however, this does not seem to be the case. In October this year, for example, a very heated debate took place on the TESP-L e-mail discussion list about whether or not English for Academic Purposes (EAP) could be considered part of ESP in general. At the Japan Conference on ESP also, clear differences in how people interpreted the meaning of ESP could be seen. Some people described ESP as simply being the teaching of English for any purpose that could be specified. Others, however, were more precise, describing it as the teaching of English used in academic studies or the teaching of English for vocational or professional purposes.
At the conference, guests were honored to have as the main speaker, Tony Dudley-Evans, co-editor of the ESP Journal mentioned above. Very aware of the current confusion amongst the ESP community in Japan, Dudley-Evans set out in his one hour speech to clarify the meaning of ESP, giving an extended definition of ESP in terms of 'absolute' and 'variable' characteristics (see below)