These recommendations formed the basis of the 'Extensions to the IPA' ('extIPA' for short, pronounced [ɛkˈstaɪpə] on the model of "JIPA" [ˈdʒaɪpə]) [...] While the extIPA symbols were drawn up mainly to aid those working within clinical phonetics and speech pathology, there is, of course, no reason why phoneticians working on non-disordered speech should not adopt some of the conventions introduced in extIPA.
Source: wiktionary