Hello! I am interested in words that, over time, have lost the sound of some of the consonants that make up the word.

Is Comharsa (Neighbor) an example?

What about Comhaireamh (counting).

How about Tabhair (give)

What sounds have been lost? What are some other words like this?

Thank you for your time.

I don't know if I would classify the examples that you gave as 'lost consonant sounds'. Sure, in most dialects, the consonant itself has been largely lost and very different from what would be the original phoneme (e.g. comharsa --> /kõ:rsə/ in Munster), but even with that a new phonetical realisation has occured, that being the lengthening of the /o/ vowel (which in some cases has become /u: ~ ũ:/). In some dialects in Ulster, the original phoneme (in the examples you provided) has been preserved to an even higher level (i.e. /kowərsə/), but I believe that the modern dialects in the north that preserve this are now few as a result of the imperialistic and oversimplified Caighdeán. There are some phonemes, however, that have been virtually erased throughout all dialects as distinct phonemes, such as the fortis or strong /r/ phoneme (i.e. /R/ or /ʀ/ as many Irish linguists right it), which is essentially a trill as opposed to the normal flap. No dialect that I know of has this as a distinct phoneme that would occur in the environments where it would have normally be found (i.e. at the beginning of (most) words in unlenited contexts, and before dental consonants). The strong/fortis slender /r/ (/R´/ or /ʀ´/) has for sure disappeared in every dialect. But I don't think that this is the kind of 'phantom consonant' that maybe you were asking about?

_________________
I'm an intermediate speaker of the Corca Dhuibhne dialect of Irish and also have knowledge on the old spelling
Soir gaċ síar, fé ḋeireaḋ thíar

Sorry to ressurect a dead post... but I found a good example.

Google AI is telling me that in old Irish, the 'mh' in comhairle makes a v or w sound, whilst in modern Irish this sound is lost. Are there more examples like this?

I didn't see this when you first posted it, so I'll jump in here.

Firstly, Google AI is not to be trusted. The lenition of m in Old Irish would not be expected to be represented by mh. It would typically have not been shown in the orthography at all, in fact, though the reader would be expected to know that it would occur in certain situations. Hence, in eDIL, the headword for the word you've just asked about is actually written comairle. Moreover, in Old Irish the m would not have made a w sound, though it actually does in Modern Irish. The sound has never been entirely "lost", just softened over time.

To go back to your original question, the answer is yes. In fact, the majority of word-internal and word-final consonants "lost" their sound somewhere between the Archaic Irish and Modern Irish periods. This happened for a wide variety of reasons, too extensive to discuss in one thread, though if you're interested I'd strongly suggest looking into learning Old Irish, or perhaps just reading through David Stifter's book on Old Irish for beginners, Sengoidelc, as a reference.

As a caveat, which Séamus already mentioned to you, while consonants may have lost their original or consonantal sounds, the sound of the word as a whole may have changed in many cases to accommodate this, and the consonant may still be pronounced (i.e. as a diphthong or a w). As such, it might be argued that the consonant was never "lost", just that it is now realised differently.

As for your examples...

Any word beginning with com(h)- should be treated as something of a compound as this prefix can be attached to many words, with a meaning like English "co-". Com(h)airle can be understood as a combination of com(h)- "co-" and airle "the act of advising", hence, "co-advising" or "counsel". Similarly, com(h)arsa seems to be a combination of com(h)- with airsa "a door-post" or "jamb", hence "co-door-post", or "neighbour". Both of these terms can be found in relatively early sources, which suggests that they likely were pronounced with a hard m at some point in their prehistory, and likely with a bilabial "v" sound in the Old Irish period. This is not always going to be the case, though, as comh- is still a productive prefix in Modern Irish, so any examples which cannot be reliably traced back to, or before, the Middle Irish period may never have been used or pronounced with anything other than the modern phonetics. In the case of comhaireamh "counting", for example, this looks like it may be a more recent combination using comh-. The Old Irish verb "to count" was ad-rími, which clearly is a part of this combination in the form aireamh, but I can't say that this verb was attested with the prefix com- in Old Irish sources. The compound doesn't seem to have a separate entry in eDIL, and the entry for ad-rími doesn't list any examples where it is combined with com(h)-. As such, it might be a much newer combination, and may never have had a consonantal pronunciation of the m.

The verb tabhair "give" is easier. This goes back to the Old Irish compound verb do-beir, which had a dependent (prototonic) form, (ní) tabair "(did not) give". This is a combination of the preverb do- and the simple verb beirid (Modern Irish beir) "to bear". In the independent (deuterotonic) form, do-beir, the b would have been fully stressed, and hence felt as if it were the beginning of the word. As such, it would have had the full consonantal sound of the letter b. In the prototonic form, (ní) tabair, the stress would shift to the preverb, and the b would have been felt as if it were word-internal, hence, it would have been softened in pronunciation to a v sound. This later developed further into the even softer Modern Irish w sound for word-internal bh.

Wow. Thanks for the great response. One more question in this direction:

What is with all the silent "gh" sounds? My last name has this feature, as does the word for heal, "leigheas."

Was this always silent? In the case of my last name, (Vaughn), I've heard that it comes from the genitive form of Mochán, or "The early ones", and thus the "gh" used to not be silent and rather sound like a "k" or "c" sound.

Vaughn seems to be of Welsh origin, from bychan, meaning something like "small". djwebb already told you this here. In the same thread, Labhrás mentioned that the Gaelic name, Ó Mocháin, has often been anglicised (incorrectly I might add) as Vaughan. The same is true of the name Mac Mathghamhna/Mac Mathúna, as it happens. The names just sounded close enough to each other to have become conflated by English speakers in Ireland, but one did not develop from the other.

The point to note is that the gh in Vaugh(a)n developed out of Middle Welsh, not Irish, so while there may be parallels, nothing I've said in this thread can be taken to apply to the gh of Vaugh(a)n. There is no developmental relationship between the ch of Ó Mocháin and the gh of Vaugh(a)n. You do get gh in Irish surnames, of course, like Gallagher. Here it's pronounced more like a h, rather than being silent, though this is just one anglicisation of an Irish surname. In Irish the gh is often pronounced in some sense. Taking your example, the gh in leigheas is generally pronounced as a diphthong, a͜ɪ, as in the English words, "might" and "light". I think the Ulster dialect might be an exception to this, but that's not my area.

In short, where you see gh in Modern Irish, it was not always silent, no. Even in Modern Irish, it may still not be totally silent, though it will likely have been pronounced more like a consonant at some point in the language's history. This is a generalisation, though, not a hard rule.

In every modern dialect of Irish, dh and gh have disappeared as distinct consonant sounds when not at the beginning of the word, with two 'exceptions': dh and gh maintain their guttural pronunciations in compound words (though this could instead be viewed as the beginning of a sperate word that has been compounded on to the other one) such as ciardhubh; and, in Munster, slender dh and gh are pronounced as slender g (so, again, this isn't really an exception as it does not maintain a distinct pronunciation, as it is not realised as /ɣ/ as one might expect). One could argue that in Ulster the distinct pronunciation is maintained under some circumstances, such as in the word caighean, which is realised as /kai(j)ən/, but I would argue that this is rather that maintaining of two distinct syllables, rather than the merging into one diphthong as is common across dialects. This table sums up the loss of the medial dh/gh pretty well: https://en.wikipedia.org/wiki/Irish_ort ... h%E2%9F%A9

Interestingly, as for the example you provided (Vaughn), something similar actually occurs in English, where in orthography 'gh' used to be realized as /x/ (i.e. like Irish ch), but nowadays this has completely vanished as a functioning phoneme in the same context across all dialects, as far as I'm aware.

_________________
I'm an intermediate speaker of the Corca Dhuibhne dialect of Irish and also have knowledge on the old spelling
Soir gaċ síar, fé ḋeireaḋ thíar

What about the words "adhlacadh" and "oidhreacht"?

What's the story with the "dh"?? Did they use to make some sort of sound?

Yes:

adhlacadh goes back to adnacul. The dh here was originally a voiced dental.

oidhreacht goes back to eigrecht/oigrecht. There was a phonetic conflation here, leading a historical gh to turn into dh. Originally, this would have been a voiced guttural.