I have not had time to blog in a while, and I really don’t have much time now either. But here is a quick note (one of several, I anticipate) about the past tense debate.

It is common to talk as if connectionist approaches and dual-route models are the two opposing approaches to morphological irregularity, when in fact there are three approaches. Linguists since at least Bloch (1947)¹ have claimed that regular, irregular, and semiregular patterns are all rule-governed and ontologically alike. Of course, the irregular and semiregular rules may require some degree lexical conditioning, but phonologists have rightly never seen this as some kind of defect or scandal. Chomsky & Halle (1968), Halle (1977), Rubach (1984), and Halle & Mohanan (1985) all spend quite a bit of space developing these rules, using formalisms that should be accessible to any modern-day student of phonology. These rules all the way down (henceforth RAWD) approaches are empirically adequate and have been implemented computationally with great success: some prominent instances include Yip & Sussman 1996, Albright & Hayes 2003,² and Payne 2022. It is malpractice to ignore these approaches.

One might think that RAWD has more in common with dual-route approaches than with connectionist thinking, but as Mark Liberman noted many years ago, that is not obviously the case. Mark Seidenberg, for instance, one of the most prominent Old Connectionists, has argued that there is a tendency for regulars and irregulars to share certain structural similarities. To take one example, semi-regular slept does not look so different from stepped, and the many zero past tense forms (e.g., hit, bid) end in the same phones—[t, d]—used to mark the plural. While I am not sure this is a meaningfuly generalization, it clearly is something that both connectionist and RAWD models can encode.³ This is in contradistinction to dual-route models, which have no choice but to treat these observations as coincidences. Thus, as Mark notes, connectionists and RAWD proponents find themselves allied against dual-route models.

(Mark’s post, which I recommend, continues to draw a parallel between dual-routism and bi-uniqueness which will amuse anyone interested in the history of phonology.)

Endnotes

1. This is not exactly obscure work: Bloch taught at two Ivies and was later the president of the LSA. 
2. To be fair, Albright & Hayes’s model does a rather poor job recapitulating the training data, though as they argue, it generalizes nonce words in a way consistent with human behavior.
3. For instance, one might propose that slept is exceptionally subject to a vowel shortening rule of the sort proposed by Myers (1987) but otherwise regular.

References

Albright, A. and Hayes, B. 2003. Rules vs. analogy in English past tenses: a computational/experimental study. Cognition 90(2): 119-161.
Bloch, B. 1947. English verb inflection. Language 23(4): 399-418.
Chomsky, N., and Halle, M. 1968. Sound Pattern of English. Harper & Row.
Halle, M. 1977. Tenseness, vowel shift and the phonology of back vowels in Modern English. Linguistic Inquiry 8(4): 611-625.
Halle, M., and Mohanan, K. P. 1985. Segmental phonology of Modern English. Linguistic Inquiry 16(1): 57-116.
Myers, S. 1987. Vowel shortening in English. Natural Language & Linguistic Theory 5(4): 485-518.
Payne, S. R. 2022. When collisions are a good thing: the acquisition of morphological marking. Bachelor’s thesis, University of Pennsylvania. 
Pinker, S. 1999. Words and Rules: the Ingredients of Language. Basic Books.
Rubach, J. 1984. Segmental rules of English and cyclic phonology. Language 60(1): 21-54.
Yip, K., and Sussman, G. J. 1997. Sparse representations for fast, one-shot learning. In Proceedings of the 14th National Conference on Artificial Intelligence and 9th Conference on Innovative Applications of Artificial Intelligence, pages 521-527.