Various phenomena involving the interaction of reduplication and phonology have been brought to bear on evaluating parallel versus serial theories of phonology. In Base-Reduplicant (BR) Correspondence Theory (McCarthy and Prince 1995), implemented in the classic parallel version of Optimality Theory (P-OT; Prince and Smolensky 1993/2004), the mapping from the underlying representation to the surface output is direct, without intermediate stages. In P-OT, the candidate-generating function GEN can simultaneously introduce multiple changes to the input. In contrast, the theory of Serial Template Satisfaction (STS; McCarthy, Kimper, and Mullin (MKM) 2012) is an approach to reduplication couched within Harmonic Serialism (McCarthy 2000 et seq.), a version of OT with serial evaluation that includes intermediate levels of structure. In Harmonic Serialism, GEN is restricted to making no more than one change at each derivational step, a property known as gradualness.
An argument put forth in favor of STS is that it does not admit a number of reduplicative patterns that MKM claim are unattested, which are otherwise predicted by BR Correspondence Theory in P-OT (MKM 2012:225). Among these are patterns formerly interpreted as overapplication, backcopying, and underapplication. While such patterns previously served as arguments for BR Correspondence Theory (McCarthy and Prince 1995, 1999), MKM reexamine those cases and conclude that they do not provide solid evidence against a serial approach. Among the remaining patterns, coda-skipping reduplication and derivational lookahead appear to offer the strongest arguments in favor of STS. These are the two patterns for which the parallel and serial versions of OT make quite distinct predictions. However, recent studies have called the status of arguments involving both patterns into question. Zukoff (2017) shows that STS does not actually exclude coda-skipping reduplication, because certain mechanics that STS employs to account for attested partial onset skipping would predict coda skipping. Adler and Zymet (2017) identify a reduplication pattern in Maragoli that poses a type of lookahead problem for STS: the ordering of reduplication and hiatus-driven glide formation depends on lookahead to the surface form of the reduplicant, which favors a simple onset.
In light of the ongoing discussion on these issues, this squib focuses on another kind of lookahead effect in reduplication where the amount of material copied would depend on a subsequent phonological change in the setting of a serial evaluation. Due to the stepwise gradual change in Harmonic Serialism, STS predicts that lookahead effects are not possible, while the potential for multiple, simultaneous changes in P-OT predicts that they exist. In this squib, we argue that a reduplicative affixation in Mbe instantiates a lookahead effect—specifically, one that closely resembles a hypothetical pattern that MKM identify as a problem for STS, were it to be attested. Furthermore, the variation in reduplicant size is arguably a case of “simple-syllable reduplication,” a pattern claimed not to be predicted by STS. This reduplicative pattern in Mbe is straightforwardly accounted for in P-OT. However, in STS the pattern cannot be understood as a lookahead phenomenon, which gives rise to a treatment with unwanted stipulations and complications. We consider three alternatives in STS involving allomorphy or different templatic approaches, but find shortcomings in each.