Learning Long Distance Phonotactics

Two questions regarding the non-local nature of long-distance agreement in consonantal harmony patterns (Hansson 2001, Rose and Walker 2004) are addressed: (1) How can such patterns be learned from surface forms alone? (2) How can we understand a a major feature of the typology—the absence of blocking effects? It is shown that a learner which generalizes only by making distinctions with respect to the order of sounds (and by not making distinctions with respect to the distance between sounds) is able to learn major classes of long-distance phonotactic patterns, and is unable to learn hypothetical long-distance phonotactic patterns with blocking effects. Thus not only is the learner able to acquire attested patterns, it explains the absence of unattested ones. Furthermore, this result lends support to the idea that long distance phonotactic patterns are phenomonologically distinct from spreading patterns contra the hypothesis of Strict Locality (Gafos 1999, et seq). keywords: phonotactic learning, long-distance agreement, grammatical inference, formal language theory Material in this paper was presented at the 2007 annual meeting of the LSA, and in 2008, at a phonology seminar at the University of Maryland, and at a Cognitive Science Workshop at the University of Chicago. I thank those audiences for their constructive feedback. I also thank Daniel Blanchard, Bruce Hayes, William Idsardi, Jason Riggle, James Rogers, Edward Stabler, Colin Wilson, and Kie Zuraw for valuable discussion. This research was supported by a 2008-2009 University of Delaware Research Fund (UDRF) grant.