The influence of context on learning metrical stress systems using finite-state machines
Abstract
Languages vary in the way stress is assigned to syllables within words. In this article, we investigate the learnability of stress
 systems in a wide range of languages. The stress systems can be
 described using finite-state automata with symbols indicating
 primary, secondary or no stress. Finite-state automata have been
 the focus of research in the area of grammatical inference for some
 time now. It has been shown that finite-state machines are
 learnable from examples using state-merging. One such approach,
 which aims to learn $k$-testable languages, has been applied to
 stress systems with some success. The family of $k$-testable
 languages has been shown to be efficiently learnable (in polynomial
 time). Here, we extend this approach to $k,l$-local languages by
 taking not only left context, but also right context into account.
 Furthermore, we consider empirical results. Some stress systems are
 only learnable when more examples are provided than the theoretical
 minimum. Our results show that when learning stress patterns using
 state merging, left context is more important than right context.
 Some stress systems are not learnable using either $k$-testable or
 $k,l$-local language learning system. A more complex merging
 strategy and hence language representation is required for these
 stress systems.