9. AN AS YET UNRECONSTRUCTED PPH INITIAL PHONEME - *y
In a note to PMP *qayuyu 'coconut crab: Birgus latro' in the ACD, Blust states: "Among the more than 2,200 etyma in Dempwolff (1934-38) only two, *yawak ‘monitor lizard’ and *yuyu ‘kind of large crab’, begin with *y. It is now clear that both etyma were trisyllables in which *y was medial (*bayawak, *qayuyu), and that no instances of initial *y can be reconstructed at any level in the Austronesian family tree above POc" [underscoring mine]. I beg to differ. In my ZDS under "Y-Etyma", there are more than eighty low-levelreconstructions, of which the following 18 might be assigned to PPH (under Blust's criteria), although my hypothesis is that only 12 are PPH, while 4 are PNP and 2 are PSP. While some of the functors are clearly derivable from the marker *i preceding another root, the fact remains that this resulting *y undergoes appropriate changes in those languages where *y merges with another phoneme (unlike *i).
	PPH *ya [cm-cn-sg-nom] (common noun singular nominative case marker)
	PPH *ya [deic-1-root] (1st person demonstrative root)
	PNP *ya [ligature]
	PPH *yaʔmek 'soft; smooth; easy'
	PNP *yaʔpaw 'light(weight)'
	PPH *yakál 'tree: Philippine mahagony, Shorea or Hopea sp.'
	PPH *yaken [pro-1-sg]
	PPH *yamen [pro-1-pl]
	PSP *yami [pro-1-pl], possibly PAN
	PSP *yamu [pro-2-pl]
	PNP *yápit 'thin'
	PPH *yawyaw 'angry, frustrated; baffled'
	PPH *yay [deic-1]
	PPH *yegyeg 'earthquake' [Cf: PPH *yugyug]
	PPH *yi [deic-3-root]
	PNP *yu [pro-2-pl-gen]
	PPH *yugyug 'shake' [Cf: PPH *yegyeg]
	PPH *yupyup 'inhale ~ exhale'

I have yet to encounter a Philippine dictionary that does not have a Y section. Many of the ZDS reconstructions have been drawn from or compared with the following dictionaries in descending order of citations for initial y-:
TABLE 1. Y ENTIRES IN PHILIPPINE-LANGUAGE DICTIONARIES
ENTRIES	DICTIONARY	REFERENCE	COMMENTS
208	Cebuano†	Wolff (1972)	several Spanish loans
161	Waray†	Tramp (1995)	several Spanish loans
118	Tagalog†	Panganiban (1972)	several Spanish loans
101	Ilokano†	Rubino (2000)	several Spanish loans
096	Itbayaten	Yamada (2002)	several merged *R>y
092	Hiligaynon†	Kaufmann (1934)	several Spanish loans
083	Bontok	Reid (1976)
074	Bikol	Mintz & Britancio(1985)	several Spanish loans
057	Hanunoo	Conklin (1953)
048	Aklanon	Zorc & Salas (1969)	several Spanish loans
034	Pangasinan†	Benton (1971)	a few Spanish loans
030	Agutaynen	Caabay et al. (2014)
028	Tboli†	Awed, Underwood & van Wynen (2004)
025	Kapampangan†	Forman (1971)	some mergers with *ñ
018	West.Bukidnon	Elkins (1968)
016	Isneg†	Vanoverbergh (1972)
012	Tausug	Hassan & Ashley (1994)
008	Kagayanen	Harmon (1977)
004	Arta	Kimoto (2017)
003	Tiruray	Schlegel (1971)

= = = = = = = =
PPH *ya [cm-cn-sg-nom] (common noun singular nominative case marker) | Isneg ya, Itawis ya, Malaweg ya, Botolan, Bolinaw ya, Mamanwa ya, Kalagan ya

PPH *ya [deic-1-root] (1st person demonstrative root) | Aklanon di|ya, i|ya, ra|ya ~ da|ya, Kinaray-a reg|ya, Bulalakawnon, Semirara ja [= dya], Kalamian Tagbanwa at|ia, Maranao, Iranon sa|ia, Ivatan nia|ya, Itbayaten di|ya, ni|ya

PNP *ya [ligature] | Yogad ya, Pangasinan ya, Botolan ya | Ibaloi jen (?)

PPH *yaʔmek 'soft; smooth; easy' | Yogad mE:mek 'soft', Itneg malama:mek 'soft', Kiangan Ifugao mayamʔok 'soft', Ilongot ʔuyamek 'smooth', Mansaka ma|yamek 'easy', Kagayanen yemʔek, yimʔek.

PNP *yaʔpaw 'light(weight)' | all my date is from McF NP#515 | Most evidence (I now see that it may be Central Cordilleran, not PNP) points to yapʔaw, but I believe there is a root *paw. Cf:  Itbayaten mahpaw, Ivatan maʔpaw

PPH *yakál 'tree: Philippine mahagony, Shorea or Hopea sp.' | Ilokano yakál 'a species of durable hardwood, Hopea sp., yacal tree' [Rubino 2000:645], Bontok yakal 'mahogany. A tall, softwood tree. Hopea sp. (Diptericarpac.)' [Reid 1976:325], Tagalog yakál 'Hopea flagata: yacca tree and its lumber, classified as timber of the 'first group' among Phil. lumber' [Panganiban 1972:1023], Waray yakál 'Shorea astylosa, a large tree used for house posts; Hopea flagata, its hard word is first-class timber [Tramp 1995:480], Hiligaynon yákal 'a kind of tree and its valuable timber' [Kaufmann 1934:1005], Cebuano yakál 'k.o. hardwood tree, producing extremely hard, first-class wood' [Wolff  1972:1132], Tausug yakal 'yakal (Shorea gisok)' [Hassan & Ashley 1994:536]

PPH *yaken [pro-1-sg] | Ivatan & Itbayaten yaken, Itawis ya:ken, Itneg dya:ken, Kagayanen yaken.

PPH *yamen [pro-1-pl] | Ivatan & Itbayaten yamen, Kalamian Tagbanwa yamen, Iraya yamen

PSP *yami [pro-1-pl], possibly PAN | Kalamianic yami(ʔ), Sindangan Subanen yami | And, of course the Batanic language Yami itself.

PSP *yamu [pro-2-pl] | Kalamianic yamu(ʔ), Sindangan Subanen yamu

PNP *yápit 'thin' | Isinai ya:pit [Reid-CC]mEyapit [McF-NP], Kalinga na|yapit [McF], may|yapit [Reid], Baynin Ifg ma|ha:pEt, Amganad, Batad ma|ya:pit, Balangao ya:pEt, Bontok ya:pit, Kankanaey men|ya:pit, Ilongot yapit | NagaBikol ha|yaʔpit

PPH *yawyaw 'angry, frustrated; baffled' | Ilokano yawyaw 'baffled', Dibabawon yewyew 'gnash teeth', Central Mindanao Manobo 'pass finger back & forth in fron of mouth (in anger)', Western Bukidnon yewyew 'move jaw back and forth (sign of anger)'

PPH *yay [deic-1-root] | Kayapa di|yay, Ibaloi sa|jay, ciyay [Reid], ʔi|yay, shi|yay, Casiguran Dumagat ʔe|yE, seyE; Maranao gi|yaʔi

PPH *yegyeg 'earthquake' [Cf: PPH *yugyug] | Isneg yagyag [Reid], yegyeg [McF-NP], Ilokano yegyeg, Isinai yogyog (?), Kankanaey yegyeg, Ibaloi jegjeg, Kalahan yegyeg, Pangasinan yegyeg; Samal jogjog tana

PPH *yi [deic-3-root] | Yogad yu:|yi, tu:|yi, Ilianen, Western Bukidnon ka|yi, Ata kai, Kagayanen ni|yi | Kalagan yai (?)

PNP *yu [pro-2-pl-gen] | Gaddang yo, Ilokano, Luba, Itneg, Manabo, Kalinga, Isinai, Ifguago, Balangaw, Kankanaey, Kallahan, Pangasinan, Ilongot, Kapampangan yu, Bontok, Botolan yo, Ibaloi ju | Also see: {yu[SMn][Pro-2+2-gen]=ZDS.jpg}

PPH *yugyug 'shake' [Cf: PPH *yegyeg] | Aklanon, Hiligaynon, Masbate, Cebuano yugyug, Tag yugyog, Sambal & Kapampangan yugyug; Samal yogyog; Pangasinan yugayog.

PPH *yupyup 'inhale ~ exhale' | Aklanon yupyup, Bikol yupyup, Casiguran Dumagat yopyop, Batad Ifugao, Tasaday yufyuf; Iraya puypuy (metathesis?) | Probably related to PAN *Seyup, PMP *heyup, I would say with ROOT *yup, which could not exist under your hypothesis.