palatization of y- from *ga-

Question

Premises

The common Proto-Germanic prefix *ga‑ affixed to past participles was reduced in Modern English, obscuring its historical participial morphology now beyond modern recognition, as seen for example, in:

• e‧nough.
• y‧clept.
• a‧like from Old English anlic, reinforced by Old Norse glikr.
• hand‧i‧work from Old English handġeweorc < hand + ġeweorc.
• a‧mong from Middle English ymong and this from Old English onġemang from on “in” + ġemang “mingling”.
• The regional prefix a‑ as in a-been, a-scattered, a-muddled, a-ready (which can still be found in southwest England and the southern United States).

From these examples, it seems that a simple vowel sound remained in the initial, unstressed position after any initial consonant sound before it had been worn down. We know that there had originally been one from comparison within the Germanic language family.

For several reasons that shouldn’t matter here, I still associate this prefix with palatal consonantal sounds in English, such as in:

• Modern English yearn /jɚn/ akin to Danish and German gerne /ˈɡɛrnə/ and to Faroese gjarna /ˈdʒarna/.

• The regional Low German (Plattdeutsch) for English “enough”, jenug with initial palatal /j/, (unlike standard German genug with initial /g/).

• Also Francophone gently /ˈd͡ʒɛntli/.

• The diphthongization seen in the Modern English first-person singular nominative pronoun I /aj/ with /j/ (sometimes represented as /aɪ/, and corresponding to Latin ego), that is consonantal in regional cham, "I am".

• Modern English yes /jɛs/ from Old English ġīese /ˈji͜yːse/.

Question

Does this prefix surface anywhere in a form that would ever sound like ja‑ as in English jar /d͡ʒɑr/, or at least like ya‑ as in English yahoo /ˈjɑhu/?

Rational

In this case there may be some minute chance that jam-packed could just possibly be akin to German gepackt, the past participle of packen meaning “pack” and used in virtually the same sense in German as it is in English, although often with a leading intensifier: voll, völlig ∼ full, fully.

Answer 1

This is a rather negative answer, but the full explanation would take several pages

Does the prefix surface anywhere in a form that would rhyme with ja- or at least ya-?

I have been unable to find any words that began "ga" that developed to "ja"- but absence of evidence is not evidence of absence.

There is evidence to the contrary in the word "gather". In OE, this was recorded in "gegather" (brought together = united) and this appears as

c725 Corpus Gloss. 512 Compactis, gegædradon,

but in eME, it appears as c1175

Lamb. Hom. 147 An is..þet faire icunde þet is igedered bi-twene saule and licame.

Note how the first "g" changes to "i" which was pronounced /j/: this was as the first (softened/unemphasised) "g"[1] is replaceable by the OE letter "Yogh[2] + e" but the second, hard "g" is not, and it is the yogh + vowel but not "a", because would have created the hard "g" of "gather".

However, it appears that words that began with, or contained ia- common in Latin - were all pronounced /dj/ and this is where the seems to originate.

That the "j" appeared in the first place, and yogh was lost, is most likely the Norman-French influence and also that of Church Latin and the transition to Modern English

The situation was further complicated by the letter "J", which was a comparatively late modification of the letter I, pronounced /dj/, akin to that of modern English di , de , in odious , hideous, (and Latin - tending more towards /j/ - iactus, iam, Iouem, maior, etc.) and developed to /dʒ/: Compare jump, Jove, Major).

The introduction of "J" then gave those words the initial "j".

[1]This is supported by Modern German Dialect in which, for example, "gegangen" (pp to go) is pronounced /j/egangen See Amazon music "Als wir jüngst verschütt jegangen waren" https://www.amazon.de/-/en/dp/B007WHAW8Y

[2] OED: (The name of) the letter ȝ commonly used in Middle English to represent the palatal semivowel /j/, the voiced velar fricative /ɣ/, or the unvoiced velar fricative /x/.The letter ȝ developed from a form of g in Anglo-Saxon manuscript writing (ᵹ) and became distinguished from the continental form of the letter (the ancestor of modern lower-case g) in the early Middle English period.