Tham khảo tài liệu 'sound patterns of spoken english phần 5', ngoại ngữ, kỹ năng nghe tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 60 Attempts at Phonological Explanation of their environment with dental alveolar as a default value . the one which is assumed if no other feature takes over. Spreading occurs when a feature fills an underspecified slot in an adjacent unit. Lodge p. 25 suggests that 2 is true because subsystems within a language can undergo different processes onset position conditions the early specification of place for coronals whereas coda position does not. In addition Lodge also assumes p. 28 that Ỗ is underspecified for manner since it retains its place but can assimilate in manner to preceding consonants. Firthian prosodies Several linguists Kelly and Local 1989 Simpson 1992 Ogden 1999 advocate an approach which they describe as a development from the theories of J. R. Firth 1957 . According to these researchers phonology is done at an abstract algebraic level and everything else is phonetics. This technique maps directly from citation form to surface form without attributing any special significance to the phoneme or any other abstractly-defined unit. Given a string of lexical items in citation form it assigns features to portions of an utterance resulting in a nasalized labialized or otherwise phonetically realized section which does not necessarily correspond to an even number of underlying phonological units. An important assumption here is that there is no significant structural change in the spoken form the citation form is produced or performed using components which decide its phonetic identity. Some performances may have little or no acoustic reflex of particular phonological units as a result of the way the prosodies interact. A useful analogy might be with stops on an organ which allow the input musical patterns to be realized in different ways and which can be switched in and out at independent intervals even in the middle of a note. If these prosodies are thought of as gestures there is considerable superficial similarity to the articulatory approach
