This is quite common. I would argue that that Georgian pattern is almost the same thing as the aspirated-unvoiced-ejective pattern. This variant where the plain stop is voiced occurs frequently in other Caucasian languages as well as Georgian, and also shows up pretty frequently in North America.
To start looking for answers to questions like this, I would recommend this UPSID search tool, mixed with a little bit of programming and/or manual sorting.
This is a way of searching the UCLA Phonological Segment Inventory Database. This is a database of the phonetic inventories of 451 languages. These languages were chosen to be representative of human languages as a whole. It is not an attempt to record the phonetic inventories of every language, as can be seen by the fact that it doesn't even have English. If you're a little more adventurous, you could try downloading PHOIBLE 2.0 and writing software to search through that. That's a database with over 3000 phonological inventories.
A simple way to start would be to look for every language where unvoiced stops of the aspirated pulmonic, unaspirated pulmonic, and unaspirated ejective types occur.
So, I on three tabs of the search engine. I search for:
- voiceless, no aspiration etc., plosive
- voiceless, aspirated, plosive
- voiceless, ejective-stop
I then copy the the languages list sections of the output pages, including all the messy numbers and phoneme lists and stuff, and assign them to 3 variables in Python 3.7.5 (which I have on my computer) based on which search they came from.
t = '''<insert text from voiceless, no aspiration etc., plosive>'''.split()
th = '''<insert text from voiceless, aspirated, plosive>'''.split()
tt = '''<insert text from voiceless, ejective-stop>'''.split()
.split() function here converts these strings of text into lists of strings using any spaces as dividers.
I then run a fairly simple little program to find what words are in all three lists but aren't just numbers, and without repeating everything 3 times.
for i in t:
if (i in th) and (i in tt):
mayBeAnExample = True
for j in i:
if j not in "ABCDEFGHIJKLMNOPQRSTUV-!?'~":
mayBeAnExample = False
Note that "ABCDEFGHIJKLMNOPQRSTUV-!?'~" is every character used in UPSID language names, as can be seen on this page: http://web.phonetik.uni-frankfurt.de/upsid_languages.html
I get the following input back:
Now, the method I used involves splitting the text up into different words using spaces as dividers, but some of the UPSID languages have multi-word names, so I have to check against the names against http://web.phonetik.uni-frankfurt.de/upsid_languages.html to see if there are any that have been messed up by my program. (Actually, I don't in this case because I recognize these names from similar searches I've done very recently, but, in general, you might have to.)
In this output we can see that the last three words need to be fixed. The first "SOUTHERN" comes from "SOUTHERN KIWAI" (a Trans-New-Guinea language), which has plain voiceless stops, but not the other two. Southern Nambiquara, however, (a language from Matto Grosso Brazil) has all three types of stop (as well as two implosives), so both instances of the word "SOUTHERN" got taken along for the ride and accepted, while "KIWAI" was correctly omitted.
Thus our fixed list is:
- SOUTHERN NAMBIQUARA
19 languages out of 451 = 4.21%, so now you know what it actually means when I say that something is "quite common". It's interesting to note that all of these languages are from either the Americas or the Caucasus. It's also worth noting that some of these languages have more than just these three series of stops, like how I already said Southern Nambiquara has implosives. You can look each of them up to find out. Also, for each language on this list, you can probably find several more in the same language family or part of the world.
You may have noticed that the UPSID describes what you and Wikipedia say are voiced stops in Georgian as actually voiceless stops. Perhaps this is dialectical variation. UPSID really just records one dialect of each language, and the language names it uses are sometimes too vague to even look up the precise language easily. Alternatively, this could just be a different interpretation or just error on someone's part.
It is worth noting that plain unvoiced stops sound fairly similar to plain voiced stops. Complicating this even further, Germanic languages like English often pronounce their "voiced" stops as plain voiceless stops in positions where our "voiceless" stops would always be aspirated. This is part of why plain voiceless stops sound voiced to English speakers in certain parts of words. This sort of thing is, no doubt, why they are often written as such in the orthographies of languages. This all makes sense when you consider that there is actually a continuum from voiced to unvoiced to aspirated, when thought of in terms of voicing onset time. Different languages place the allophones of their phonemes on this spectrum differently.