OT offers a tool to see how a surface structure is derived from an underlying one. Autosegmental phonology also allows us to see how a surface form can be derived from an underlying representation.

Is this comparison accurate? I'm afraid not because many rules of OT are based in autosegmental theory.

Can someone help me sort out how I should consider these two "things" (tools?)?

Thanks a lot.

1 Answer 1


The motivation underlying autosegmental phonology is that phonological processes frequently are not well-described by the 1-to-1 feature-to-segment relations assumed in SPE phonology, especially in the domain of tone. OT was motivated by a desire to reduce phonological mappings to just the notion of constraint, without any (language specific) component of "do this" (only "don't do that"). Neither theory has anything to do with the notion of deriving phones from phonemes, and neither theory assumes that "phone" or "phoneme" is a valid concept. Both theories are logically consistent with the concept of "phonetic implementation" which may provide pronunciation details such as nasalization in English, devoicing of sonorants after aspirated stops and fricatives, and so on. However, both OT and ASP are grammatical theories which deal in categorial processes, and it is generally recognized that most allophonic variation has to be dealt with phonetically and quantitatively. (ASP and OT phonetic models do, of course, exist, just as there is such a thing as OT syntax though not autosegmental syntax)

There are no rules in OT, so OT rules aren't based in autosegmental phonology. OT practicioners have largely (but not entirely) abandoned autosegmental phonology or any other theory of representation, partly because questions of representation are orthogonal, and partly because it was held that the motivation for ASP was how it allows a better account of phonological rules (correct, I would say), and therefore if the theory presupposes rules, it must be wrong. At this point, I don't think many OT practicioners care about autosegmental phonology, one way or the other.

  • Great reply. Thanks. So to summarize, both OT and ASR are grammatical theories concerned with categorical processes related to "phonetic implementation" (a new term for me), but the former does so with constraints, and the latter originates from a rule based approach. Is this an accurate distillation?
    – Teusz
    Mar 9, 2015 at 5:59
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    I would drop the "related to phonetic implementation" part since proceeding into physical implementation is not essential to either. And autosegmental analysis typically used rules since it was developed in the era when we had rules – in other words, it's not really separate from ('originate from') rule theory.
    – user6726
    Mar 9, 2015 at 16:33
  • But aren't both OT an ASR concerned with derivation of surface forms from underlying ones?
    – Teusz
    Mar 10, 2015 at 6:00
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    "Surface form" would roughly be "phonemic transcription" so it is still symbolic and categorial, whereas phonetic implemnetation is continuous articulatory movements and resulting waveforms, i.e. how the output of the phonology is realized. However, one can have autosegmental-aware or optimality based theories of phonetic implementation, but that isn't a essential part of an OT / ASP phonology.
    – user6726
    Mar 10, 2015 at 15:47

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