Modeling Reduplication with 2-way Finite-State Transducers

Abstract

This article describes a novel approach to the computational modeling of reduplication. Reduplication is a well-studied linguistic phenomenon. However, it is often treated as a stumbling block within finite-state treatments of morphology. Most finite-state implementations of computational morphology cannot adequately capture the productivity of unbounded copying in reduplication, nor can they adequately capture bounded copying. We show that an understudied type of finite-state machines, two-way finite-state transducers (2way FSTs), captures virtually all reduplicative processes, including total reduplication. 2-way FSTs can model reduplicative typology in a way which is convenient, easy to design and debug in practice, and linguisticallymotivated. By virtue of being finite-state, 2way FSTs are likewise incorporable into existing finite-state systems and programs. A small but representative typology of reduplicative processes is described in this article, alongside their corresponding 2-way FST models.

RedTyp: A Database of Reduplication with Computational Models

“…For researchers interested in learning natural language patterns, RedTyp provides a computationally explicit set of learning targets. In fact, We have used RedTyp ourselves to get typological generalizations and learnability results (Dolatian and Heinz, 2018a).…”

“…We are currently investigating some promising subclasses of 2-way FSTs. One subclass in particular is the C-OSL subclass which covers the bulk of reduplicative typology and for which there are learnability results (Dolatian and Heinz, 2018a).…”

“…Second, RedTyp models reduplicative processes with an understudied and under-used type of finite-state technology: 2-way deterministic finite-state transducers (2-way FSTs) (Engelfriet and Hoogeboom, 2001;Filiot and Reynier, 2016). As we explain in Subsection 2.2, and in detail in Dolatian and Heinz (2018b), 2-way FSTs can reread parts of the input string, unlike 1-way FSTs. In addition to allowing 2-way FSTs to model total reduplication exactly, this additional capacity significantly reduces the number of states needed to model partial reduplication.…”

“…Besides their state efficiency and practical utility, 2-way FSTs likewise capture the intensional description of reduplication. For more discussion of the role of 2-way FSTs as computational models of reduplication, see Dolatian and Heinz (2018b).…”

“…A fuller technical illustration can be found inDolatian and Heinz (2018b), and a more informal one inDolatian and Heinz (In press. ).…”