How allomorphic is English article allomorphy?

Abstract

The question of how to distinguish allomorphy from phonology plays a central role in morphological theory. While English a/an has been cited as a hallmark case of “phrasal” allomorphy, the parallel alternation between /.i/ and /.ə/ in the English definite article (/.ə/ book, /.i/ apple) has not received as much attention. This paper provides a formal analysis of English a/an and /.i/~/.ə/. I argue that: (i) /.i/~/.ə/ is not allomorphic, but is derived by the same phonological rules (tensing and vowel-reduction) as other V~ə alternations in English; and (ii) a/an involves a two-tiered derivation: first allomorphy establishes a basic split between V and Vn; then the same phonological rules involved in the (tensing and vowel-reduction) derive the four surface variants /ej/, /æn/, /ə/, and /ən/. In other words, in addition to its basic n~Ø alternation, a/an also participates in the same V~ə alternation as other strong-weak function-word pairs in English (/.i/~/.ə/ in the, /kæn/~/kən/ in can, etc.). This two-tiered serialist approach is incompatible with analyses of a/an as surface phonological optimization, or TETU (Mascaró 1996b). Accordingly, I provide evidence from emphatic glottal stops, /h/‑deletion and pause-fillers showing that despite initial appearances, neither a/an nor /.i/~/.ə/ is driven by surface syllable well-formedness constraints.