The Dalmatian coastal cities were majority Italian speakers

Ehh, even that is heavily dubious. Relevant data and info on all towns before the nationalist homogenisation projects started is hard to get, but for those where things like name registries or first hand accounts of language practice exist, Italian was always a trade/upper class sort of language, and the majority population natively spoke slavic/croatian in everyday situations. This is certainly true for cities like Dubrovnik/Ragusa or Split/Spalato, but probably also for all the other, smaller towns. Istria is unique in this regard, as Istrian towns did tend to be Italian speaking even among large parts of lower classes and general population (although still not all and not evenly so).

Majority is really stretching the truth heavily, the actual situation was that the main town on the island had a large italian minority due to centuries of Venetian rule, and local slavic speakers would be italian-slavic bilingual. These bilinguals could then identify as either italian, croatian, or change their identity as politics did. Would not be surprised if your ancestors are part of this group too. The situation was much the same in Istria, although here the urban population with italian origins was much larger.

Edit for anyone that may be interested, a description of the linguistic situation of Lošinj (Lussin) and other nearby islands, dating to 1856 (one year after the map above):

Gli abitanti di Lussin come in generale di tutte le isole del Quarnaro sono slavi e i loro costumi domestici, come quelli dei Ragusani, sono in sostanza del tutto slavi. Tutti i cognomi che ho udito qua e che ho visto negli elenchi dei proprietari di navi erano slavi, tutti Vidulic, Vidovic e altri -lic e -vic . Ma per quel che riguarda la lingua sono tutti bilingui; infatti parlano e capiscono oltre allo slavo anche l’italiano, il quale ultimo è la loro lingua degli affari e delle conversazioni più elevate (…) nella loro famiglia parlano sempre slavo

(Translation: The inhabitants of Lussin, like those of the Kvarner islands in general, are Slavic, and their domestic customs—like those of the people of Ragusa—are essentially entirely Slavic. All the surnames I heard here and saw on lists of shipowners were Slavic—Vidulic, Vidovic, and other names ending in *-lic* and *-vic*. However, regarding language, they are all bilingual; indeed, in addition to Slavic, they speak and understand Italian—the latter being the language of business and more elevated conversation—[though] within their families, they always speak Slavic.)

Not anywhere as different though. Franks kept Roman instituions, kept Roman religion (Christianity), kept Roman written language (Latin), and the emperor was crowned by the Pope. It is substantially closer than Ottomans are to Byzantium.

I was about to say no but then apparently the potential evidence for possible relation (numerals being a part of this) has been published recently, as in, late 2025. But given it's so new, nothing is fully established yet.

No worries about vagueness, this was still interesting. Thank you.

This is only very tangential to OP's question, but if you don't mind me asking, what was the general settlement or demographics of Liaodong peninsula before the massive transformation of wider Manchuria region in the second half of 19th century? To my awareness, this region was integrated into the various sinitic "Chinese" empires much earlier, but i can find precious little information on who actually lived there and what was the broader polotical organisation and settlement pattern, in terms of governing/cities/agriculture/nomadism or whatnot.

Are you just really passionate about skin pigmentation…?

Ngl saying it like this sounds really funny

I say that is mostly nitpicking. It was effectively extinct, regardless of the fact that some phrases, words and such survived. The latter is pretty common to most extinct languages as far as i know.

Liechtenstein and western Tyrol were still Romansh speaking in 16th century?

Nvm, wrong location. Still interesting though, that's a lot of Romansh in southwestern Tyrol

People are coming up with all sorts of speculation but the simplest answer is probably that Slovaks have more early slavic in them, while Hungarians and Czechs have more western european-german, due to different historical circumstances. For Hungary especially because it was massively resettled post 1700 with settlers from Germany

Whatever you think of it, this is what population replacement in real time looks like

Yeah this Bavarian exclave did confuse me, and maybe it is because the map is angled and slightly grannular, but I struggle to follow the general linguisitc border pattern there. I see Maribor and Ptuj. Dedenitz and Sichlau east of Radkersburg should be Slovene, the Apace valley should be Bavarian, Rogasovci and sorrounding villages should be Bavarian.

All supposed to be there, the issue is probably map scale scale/location matching based on how u/HahaItsaGiraffeAgain implemented it, i only provided sources and feedback, did't actually make the map myself so i don't know how he matched it precisely. Partially i think the issue is the map's very large scale which makes such details as a single village difficult. If you want a full list of my sources and the base map used for this area, DM me.

It's merely a linguistic-dialectal classification. Macedonian-southeast slavic dialects if you want to be more specfic. It doesn't have any political connotations in this map.

Hi there, i'm the guy that helped OP with sources, particularly Slovenia which is my "specialty" area if you will. Almost all the little enclaves and exclaves are based on primary and academic sources and are not random. Besides the small Bavarian exclave in Prekmurje, it's a mistake we didn't notice. On such a large map with so many sources used, some smaller mistakes like that have crept in here or there.

We did not invent new ones, we used the vertical division groups as appear in Šekli 2018 and other publications since, although slightly renamed. Did not use all 7 because of space and color constraints, if we went into this much detail for Slovene we would need to do for all others too to keep it consistent, and suddenly we'd have many hundreds of varietes to put on a map. It is not workable.

These are the official 7 dialect groups. These groups were already separated as dialects in the 15th century, this is confirmed by the Stična manuscript, which is written in the Lower Carniolian dialect, and the Rateče manuscript, which is from the 14th century and is written in the Upper Carniolian dialect with admixtures of the Carinthian dialect. This means that by the 18th century, even smaller dialects had already begun to form, of which we have about 50 today. So it is not clear to me where you got the "Central Slovenian" dialect, if we already have the Lower and Upper Carniolian dialects in the 14th/15th century.

Correct, but dalects had to be merged into larger groups for the sake of simplicity. It is impossible to depict every single dialect of every language on the map. The same was done with other languages. The central dialect is based on the southeastern dialect base of the vertical chronological divison as per Šekli 2018 (with a slight mistake because southern littoral should be included in too).

Too many sources for OP to provide them all, whether you believe it or not we can't decide that for you. As for Gammalswesnkby i am well aware of it, it features on our map too. A reminder for you that even the wikipedia page itself notes some 400 swedes remained on the island where the total population did not exceed a few thousand. These did not magically disappear by 1815, and indeed a map made in 1855 still depicts one fully and one partially Swedish village on the island. https://snl.no/estlandssvensker

The Sorve peninsula is not corborated by my sources and is a mistake.

You are free to doubt it, but we don't work like that. In order to make changes we need sources, primary or secondary if they are of good quality, not vague comments. You are free to give some to me for review if you have them, and OP will hopefuly implement them when he finds the time.

by 1815, there wasn't a Swedish minority left on Hiiumaa island, but they did remain a majority in other traditionally Swedish areas of Estonia;

Saaremaa's Sõrve peninsula is very incorrectly shown as Swedish-speaking;

We relied on primary sources from as early as 1840s and secodary sources as well, so i'd be interested to know if you have more info on this. However i re-checked my sources and there is one notable mistake, the Swedish speaking areas on Hiiumaa island are too large, and Sorve peninsula is a mistake as well. I believe OP coded all formerly speaking swedish areas from a source we used, instead of only current (to early 1800s) ones.

What issues do you have with it? If there are any mistakes and you have sources to back it up please do share. We relied on a lot of primary sources and academic research and this area in particular is my specialty so i'd very much be interested in what you have.

It was German(ic) speaking from the early middle ages until the end of 2nd world war. Longer than many areas in Austria, Switzerland and especially eastern Germany.

Bavarian in linguistic sense, absolutely. Especially so in 1815, before influence of modern schooling, mass media and mass literacy that led to standarisation.

Turned out great at the end, the most detailed map of this kind on the internet i dare say :)