Clements (1985): the geometry of phonological features #

Clements replaces the SPE feature matrix by a tree of class nodes: a root node linked to the CV tier, a laryngeal and a supralaryngeal node below it, a manner and a place node below supralaryngeal, and each terminal feature hanging from one class node (his (3) and Appendix; §4 gives the content of each node). Assimilation is the spreading of one node ((5), after Mohanan), so the theory admits three types, total (the root), partial (a class node) and single-feature, and a rule that must reach two features with no common class node below supralaryngeal is total supralaryngeal assimilation, which is why the SPE rule (14) with [αnasal] in place of [αanterior] is unattested. The evidence is English coronal place assimilation ((10)–(13)), Icelandic preaspiration ((6)–(7), after Thráinsson), Klamath lateral rules ((8)–(9), after Barker), Sierra Popoluca nasalisation and release ((15)–(20), after Elson and Steriade's Shared Features Convention) and the Kikuyu and palatalisation cases of §5, and §4 splits the place features into a primary set P, present in consonants and vowels, and a secondary set S, normally absent from plain consonants. The tree is an instance of Phonology/FeatureGeometry.lean; its manner node, which the paper itself flags as possibly superfluous, is dropped by the later geometries formalized here (Studies/Sagey1986.lean, Studies/HalleVauxWolfe2000.lean).

Main definitions #

Node, Node.pred, classNode? — the five class nodes of (3), the tree, and the class node each terminal feature hangs from (§4); together the FeatureGeometry instance.
PlaceSet, placeSet?, PlaceSet.features — the primary/secondary split of the place features (§4).
Spreading, Spreading.features, Spreading.apply — what one rule may spread, the root, a class node or one feature ((5)), and the assimilation it effects.
rule12, rule14, rule14Nasal — the English rule (12) as a local rewrite rule copying the place class, its SPE statement (14) copying [anterior] and [distributed], and the [αnasal] variant the paper contrasts with it.

Main results #

supralaryngeal_subset_of_nasal_of_distributed, apply_eqOn_supralaryngeal_of_nasal_of_distributed — every spreading that reaches both [nasal] and [distributed] is total supralaryngeal assimilation, the argument against the [αnasal] variant of (14); eq_root_of_continuant_of_voice is the Kikuyu case of §5.1 and supralaryngeal_subset_of_anterior_of_continuant the palatalisation case of §5.2.
rule12_n_θ, rule12_t_θ, rule12_d_θ, rule12_n_esh — tenth, eighth, hundredth, insure from table (11): the target takes the trigger's place features and nothing else; rule12_n_p and rule12_s_θ are the non-sites.
rule14_n_θ, rule14_n_esh, no_spreading_nasal_distributed — (14) agrees with (12) on the English data, but its alpha-variables accept the [αnasal] variant that no single-node spreading can express.
preaspiration — spreading the vowel's supralaryngeal node onto the delinked first half of an aspirated geminate keeps the stop's laryngeal features ((7)), by the substrate's disjointness of sister classes.
mem_place_naturalClass_iff, primary_separates_stops — the place features are P ∪ S, and P alone separates the English stop places (table (22)).

Implementation notes #

classNode? is defined on the features the paper names and is none elsewhere, so the root's natural class is the paper's inventory rather than all of Hayes's; [labial] counts as primary by table (22). Spreading is Finset.piecewise on a node's natural class, so the trigger's unspecified features under the node replace the target's, as the delinking convention of (13) requires; single-feature spreading is Function.update (Spreading.apply_feature). The English segments are the Fragment's; its /r/ is [+anterior] where table (10) has [−anterior, −distributed], so the retroflex row of (11) (tree, dream, enrol) is not derived. The SPE rule (14) is Effect.copyRight on the two-feature set and (12) the same effect on the place class, so the comparison is between the sets a rule may copy, not between formalisms.

TODO #

The Sierra Popoluca release argument ((17)–(20)): the Shared Features Convention merges the two [−continuant] nodes of a homorganic cluster into one doubly linked node, so the insertion rule (18), which needs two such nodes, is blocked. This needs feature-level linking (Autosegmental/AR.lean), not the segment-wise spreading here.
§4's consonant–vowel asymmetries follow from plain consonants lacking S features and vowels always carrying them; the Fragment's vowels do not specify [back] and [round], so no instance is stated.

Clements (1985): the geometry of phonological features #

Main definitions #

Main results #

Implementation notes #

TODO #

References #

Class nodes #

Terminal features (§4) #

Assimilation as spreading ((5)) #

Single-node spreading against the SPE rule (14) #

English coronal place assimilation ((10)–(14)) #

Supralaryngeal spreading: Icelandic preaspiration ((6)–(7)) #

Primary and secondary place features (§4) #