3.29 Semivowel-Deletion P-28.

This is an optional but frequent low-level rule simplifying //yi// to /i/ and //wu// to /u/ after a consonant in some cases. The rule applies particularly often to Relative suffix /-yin^yun^g/ and to postposition /-w₁ugij/ 'only; still', as in /lha:l-(w)ugij/ 'only country' and /a-Iha:l-(y)in^yun^g/ 'of the country'. Some auxiliary compounds involving /-w₂u-/ (see §14.4) are also affected, as in the case of /=lhilhir-wu-/ 'to pass by (someone), grazing (him)', but only when the vowel /u/ remains on the surface; thus /=lhilhir-(w)u-ma-na/ Nonpast₂ but /=lhilhir-wa-n^g/ Past₁. Other morphemes also beginning with semivowel and homorganic vowel do not undergo deletion; note Allative-Dative /-w₁uy/ and Similative /-yi:/ 'like' in /a-lha:l-wuy/ 'to the country' and /a-lha:l-yi:/ 'like (the) country'. Verb stems beginning in /=w₂u/ /=w₁u/ or /=yi/ do not regularly show deletion in compounds.

In addition to applying after consonants (the relevant ones being nonnasal sonorants, since these are the only consonants which a semivowel can follow on the surface), the deletion applies optionally after a vowel, as in /wu:=buri-Ø-(w)ugij/ 'they were still sitting' and /wu:=buri-Ø-(y)in^yun^g/ '(the ones) who were sitting'. In rapid speech it is rather hard to hear the difference between deleted and full forms of these suffixes, and in the texts volume I have tended to use the full transcription when in doubt (this has the advantage, also, of assisting the reader in identifying morphemes).

The present rule is here distinguished from an apparently very similar rule which we have presented above as Homorganic Semivowel- Deletion P-4. Rule P-4 is a very early one, applying to a few stem-initial semivowels. After it applies, the relevant forms are treated as vowel-initial in a series of other phonological rules including Pronominal d-Insertion P-20 and VV-Contraction P-49, and the deletion applies rigorously regardless of preceding morphemes. The present rule is a low-level, optional rule applying to suffix-initial (not stem-initial) semivowels, does not feed into other rules, and is very much affected by preceding segments. In particular, when such suffixes as /-yin^yun^g/ are preceded by a stop or nasal, Hardening P-18 applies, converting the semivowel into a stop: //y// → /j/ //w // → /g/ //w₂// → /b/ Therefore, while recognising that P-4 and P-28 are rules of the same type, I prefer to separate them formally. Some readers may wish to consider them as two instances of the application of one and the same rule, applying at two distinct stages in derivations, perhaps with some version of the phonological cycle accounting for the difference in treatment of stem-initial and suffix-initial semivowels. However, in both morphological environments we are dealing with unproductive or semi-productive alternations limited to specific stems and morphemes, and in some theories we should handle them all as minor lexical alternations.

(P-28)	Semivowel-Deletion (optional)
		y		→ Ø // -____		i
		w				u