Proto-Berber Primae Waw: Is it really a /w/?

Last time I talked a bit about an interesting possible connection of how Berber and Semitic treat verbs with initial w as the first root consonant, both of them notably seem to lack the w in the underived prefix conjugation, but reappears on other derivations. Thus yaqid but causative yūqid in Semitic, and *yăqqəd but causative *yəssuɣəd in Berber.

But as I was looking into the morphology of the Berber Primae-Waw, I noticed (and Prasse noticed with me) something strange: It is true that something which becomes a *u appears in the Verb and in verbal derivations of the group of verbs like *ăqqəd, but Berber-internally it is not actually all that obvious that it's in fact a *w element. While it is plausible that *yəssəwɣəd would become *yəssuɣəd, Berber internally there is little to stop you from simply saying that it is just a plain vowel that is added to the root.

The plain vowel that is added, however, is qualitatively different from the plain vowel that is added in verbs that in the underived form have a plain vowel already. As in those kinds of verbs like *agəm 'to draw water' the plain vowel becomes *i:

This difference in behaviour is not at all implausibly explained with the presence of an ancient *w (Pre-Proto-Berber *issīgim or *issiHgim versus *issiwɣid)

The strange thing, however, and this is something Prasse noticed already, the plain vowel that appears in these roots has surprisingly v̄ like behaviour (v̄ is a "plain vowel slot" which depending on whether the vowel pattern requires low vowels or high vowels surfaces as *a or *i,*u respectively. Thus a v̄cc verb in the Aorist (which has a |low-high| pattern surfaces as agəm but in the Perfect (which has a low-high pattern) surfaces as ugăm.

This is most notable in in the nouns of instrument. Nouns of instrument in Proto-Berber are formed by a prefix *s- followed by a |low-high| pattern, where the last high vowel show up as both long and short. So:

• *ăɣnəs'to put on a veil' -> *a-s-ăgnəs'veil'
• *ălsəʔ 'to get dressed' -> *a-s-ălsuʔ 'garment', 
• *aləy 'to hang' -> *a-saləy 'hook'
• *arəʔ 'to open' > *ta-s-aruʔ-t 'key'

However things get weird with our c̄c verbs, here the instrumental noun behaves as if it is a v̄cc stem, thus:

• *ăttəl 'to wrap' gives us *a-s-atəl 'envelope of cloth'

So how should we understand this if the plain vowel that appears is supposed to come from *w? Is this *a-s-ăwtəl, and do we have to assume that *ăw > *a /_C? *wC clusters are certainly not so common in Berber, but also not so uncommon that this etymology works without a hitch. The most obvious examples are *a-wtul  pl. *i-wətl-an 'rabbit' and *a-wtəm pl. i-wətm-an 'male'. These can be resolved in a number of ways:

• The VwC cluster occurs accross a morpheme boundary, so that may cause different behaviour.
• The preceding vowel (at least in the free state) is *a and not *ă, which may have cause different behaviour.
• It is possible that these words originally had a short vowel in the stem (this is how Prasse would perhaps reconstruct them), i.e. *a-wətul and *a-wətəm.

There are not many other places where the presumably *w yields *a, but one example might be the word *t-addar-t pl. t-udr-en 'house', which is presumably derived from the verb idir pf. əddăr 'to live'. But, if we must derive this from a dropped *w, we would have to reconstruct *ta-wăddar-t pl. *ti-wədr-en. So now we have an example of not only *ăw shifting to *a but also (a)wă shifting to *a!

Another place where we would predict a *ăw in pre-Proto-Berber is in the agentive formations, which are formed with a prefix -m/n- followed by a |low-low| vowel pattern, where the last vowel may either be short or long. Thus, we see:

• ccc stems: *a-m-ărwal'a flee-er' and *e-m-ărwăl 'id.' <- *ărwəl 'to flee'
• v̄cc stems: *a-m-araw'a parent' <- *arəw 'to give birth'
• cc stems: *a-m-ădad'biter' and *e-m-ădăd 'id.' <- *ădəd'to bite'

But here instead of getting the expected a as was the case with the instrumentals, we instead find an u!

• c̄c stems: a-n-uḍăf < ?a-n-ăwḍăf 'someone who holds' <- ăṭṭəf'to hold'.

The instrumental and the agentive therefore cannot easily be reconciled, they give two different answers of what *ăw should yield.

Moreover, reconstructing *t-addar-t'house' as *ta-wăddar-t also runs into problems. At least in Ghadamsi, in a not atypical te-CăCC-e verbal noun formation, c̄c stems do show an actual *wă, e.g. ta-waɛn-e 'load, burden' < *te-wăɣn-e<- *ăqqən 'to tie up', some varieties of Tuareg seem to show the same behaviour. In verbal nouns *w does show up in other verbs as well, in Central Moroccan Berber, for example the verbal noune of ddu < *əddu'to go' is tawada < *ta-wad-a (plain vowel *a in the stem not fully understood).

But it is also clear that *w in certain contexts does really yield plain vowels, at the very least *u and *e. For example, the stative verb iwriɣ 'to be yellow' with adjective *wăraɣ- (cf. Semitic *w-r-ḳ!) has an extremely well-attested derivation *urəɣ 'gold'.

There are also clear examples of c̄c verbs with verbal nouns of this type: Central moroccan Berber lləf 'to divorce', verbal noun uluf. And also *idir pf. *əddăr 'to love' has a well-attested derivation *t-udər-t 'life'. 

Prasse would like to derive those *u's from *ta-Hədər-t, where *Hə yields u but we might be able to rewrite the rule where *wə yields u. This would get us in trouble. This gets us in trouble with i-wətm-an 'males', but that can definitely be an analogical restoration from the singular. And while we don't understand the singular t-addar-t 'house', we could explain nicely the plural *t-udr-en as coming from *ti-wədr-en then.

Sometimes *e shows up instead, such as in ăṭṭəs 'to sleep' VN eḍəs 'sleep'. In almost all cases *e is a secondary vowel harmony result of *a, but that cannot be the case for words like this. This is one of the few places in Berber where *e seems to be 'real'. It is tempting to derive it from something like *a-yəḍəs > eḍəs or *a-wiḍis > eḍəs (and then *a-wuruɣ > urəɣ).

So summarizing all these we end up with a number of conflicting outcomes for what would be assumed to be a *w. Sometimes just behaviing like a consonant *w, sometimes behaving like a plain vowel slot that can just take an low-vowel pattern (instrumentals), sometimes with as an exceptionally *u-colouring plain vowel...

I'm not really sure how to resolve these competing outcomes. Some I think could be gotten rid of as secondary, especilly the *wă/*wə outcomes, but others... I don't know. Thoughts?