In 1934, when Yuen-Ren Chao discussed the nonuniqueness of phonemic solutions,' he demonstrated that different phonological analyses presuppose different underlying concepts. The thirty years since the publication of that paper have not produced any one phonological theory to which even most linguists will subscribe. The situation is not unusual in the history of science. Scientific theories are constantly submitted to change and revision; in an empirical science, the structure is never completed. Experiments become more precise, new phenomena are revealed, new concepts are developed. At all times we must be prepared to abandon our theory, remodel the foundations, and erect a new structure. But the history of science shows also that theories which turn out to be inaccurate can yet lead to the discovery of new facts; and each new theory retains some elements of the one it has supplanted. Acceptance of one theory does not require one to reject a rival theory in toto. It is in this spirit that the present paper attempts to describe certain characteristics of Twi phonology.2 It suggests that the incorporation of certain principles of the British system-structure or prosodic approach into the phonological component of a transformational grammar of Twi may provide a simpler and more revealing description. The phonological inventory of Twi, as it might look in a transformational grammar modeled after Morris Halle, The sound pattern of Russian,3 is presented in Tables 1 and 2 as a matrix of morphonemes and a branching diagram to represent them. According to this view, speech consists of a series of segments, specified by distinctive features (DF) and boundaries (#) characterized by their effect on the features.4