We already had a good idea about the expansion of Celts, based on proto-historical accounts, fragmentary languages, and linguistic guesstimates, but the connection of Celtic with either Urnfield or slightly later Hallstatt/La Tène was always blurred, due to the lack of precise data on population movements.
The latest paper on Iberia is interesting for many details, such as:
A discrete influx of North African ancestry in certain samples before the Moorish invasion (which was probably mediated by peoples of North African rather than Levantine admixture).
The finding of very Mycenaean-like Greek colonies of the 5th century (interestingly, under R1b lineages).
The paper is, however, of particular importance from the perspective of historical linguistics. It confirms that:
Celtic-speaking peoples expanded in Iberia likely during the Late Bronze Age – Early Iron Age (probably with the Urnfield culture, before 1000 BC) with North/Central European ancestry.
NOTE. The paper marks what are believed to be the boundaries of non-Indo-European languages during the Iron Age in later times, extrapolating that situation to the past. Mediterranean sites with Iberian traits (ca. 6th century on) were probably non-Indo-European-speaking tribes, but it is unclear what happened in the centuries before their sampling, and there are no clear boundaries. These incoming Celts from central Europe with the Urnfield culture makes it very likely that the Iberian expansion to the north happened later, incorporating thus this central European ancestry in the process. The southern (orientalizing, Tartessian) site of La Angorrilla shows incineration and influence from Phoenician settlers, and their actual language is also far from clear. The other investigated samples, with higher central European contribution, are from Celtiberian sites.
The slightly later arrival of (Phoenician, Greek and) Latin-speaking peoples into Iberia is marked by Central/Eastern Mediterranean and North African ancestry.
While both confirm what was more or less already known about the oldest attested NWIE dialects, and further support the role of East Bell Beakers in expanding North-West Indo-European, the first part is interesting for two main reasons:
Koch’sCeltic from the West hypothesis, which made a recent comeback with a renewed model based on “steppe ancestry”, is once again rejected in population genomics, as expected. At this point I doubt this will mean anything to the supporters of the theory (because you can propose as many “Celtic-over-Celtic” layers as you want), but if you are not obsessed with autochthonous continuity of Celtic languages in the Atlantic area we might begin to judge the most correct dialectal split (and thus classification) among those proposed to date, based on ancestry and haplogroup expansions.
We believed in the 2000s that the expansion of haplogroup R1b-M167 (TMRCA ca. 1100 BC for YTree or 1700 BC for YFull) was coupled with the expansion of Iberians from the Pyrenees, in turn (thus) closely related to Basques. This non-IE presence has been contested with toponymic data in linguistics, and with the testing of many modern samples and the subsequent discovery of the widespread distribution of the subclade in western and northern Europe. Now it has become even more likely (lacking confirmation with aDNA) that this haplogroup expanded with Celts.
NOTE. Regarding R1b SNPs, YTree has more samples (and thus more SNPs) to work with estimates, due to its connection with FTDNA groups, so it is in principle more reliable (although estimates were calculated in 2017). Nevertheless, the methods to estimate the age of the MRCA are different between YTree and YFull.
Why this is important has to do with the realization that Celts must have expanded explosively in all directions during the estimated range for Common Celtic (ca. 1500-1000 BC), and as such R1b-M167 is probably going to be one of the clear Y-DNA markers of the Celtic expansion, when it appears in the ancient DNA record, maybe in new SNP calls from samples of the Olalde et al. (2019) paper, or in future Urnfield/Hallstatt/La Tène papers.
Sister clades derived from R1b-Z262 (TMRCA ca. 1650 BC for YTree, or 2700 for YFull), although sharing a quite old origin, may have taken part in the same communities that expanded R1b-M167, likely from some point in central Europe, possibly as remnants of a previous (Tumulus culture?) central European expansion, as the sample SZ5 from Szólád (R1b-CTS1595) and the distribution of modern samples suggest.
The Celtic expansion might not have been a mass migration of peoples replacing all male lines of their controlled territories (as was common in the Neolithic and Chalcolithic), because of the Bronze Age dominant chiefdom-based system that relied on alliances, but it is becoming clear that Early Celts are also going to show the expansion of certain successful male lineages.
Oh, and you can say goodbye to the autochthonous “Vasconic = R1b-DF27” (latest heir of the “Vasconic = R1b-P312”) theory, too, if – for some strange reason – you hadn’t already.
EDIT (16 MAR) Just in case the wording is not clear: the fact that this haplogroup most likely expanded with Celts does not mean that its lineages didn’t become eventually incorporated into Iberian cultures and adopted non-IE languages: some of them probably did at some point, in some regions of northern Iberia, and most were certainly later incorporated to the Roman civilization and spoke Latin, then to the medieval kingdoms with their languages, and so on until the present day… Only those eventually associated with Iron Age Aquitanians may have retained their non-IE language, unless those lineages today associated with Basques were incorporated later to the Basque-speaking regions by expanding medieval kingdoms. A complex picture repeated everywhere in Europe: no haplogroup+language continuity in sight, anywhere.
NOTE: This here is currently the most likely interpretation of data based on estimations of mutations; it is not confirmed with ancient samples.
We assembled genome-wide data from 271 ancient Iberians, of whom 176 are from the largely unsampled period after 2000 BCE, thereby providing a high-resolution time transect of the Iberian Peninsula. We document high genetic substructure between northwestern and southeastern hunter-gatherers before the spread of farming. We reveal sporadic contacts between Iberia and North Africa by ~2500 BCE and, by ~2000 BCE, the replacement of 40% of Iberia’s ancestry and nearly 100% of its Y-chromosomes by people with Steppe ancestry. We show that, in the Iron Age, Steppe ancestry had spread not only into Indo-European–speaking regions but also into non-Indo-European–speaking ones, and we reveal that present-day Basques are best described as a typical Iron Age population without the admixture events that later affected the rest of Iberia. Additionally, we document how, beginning at least in the Roman period, the ancestry of the peninsula was transformed by gene flow from North Africa and the eastern Mediterranean.
From the Bronze Age (~2200–900 BCE), we increase the available dataset (6, 7, 17) from 7 to 60 individuals and show how ancestry from the Pontic-Caspian steppe (Steppe ancestry) appeared throughout Iberia in this period (Fig. 1, C and D), albeit with less impact in the south (table S13). The earliest evidence is in 14 individuals dated to ~2500–2000 BCE who coexisted with local people without Steppe ancestry (Fig. 2B). These groups lived in close proximity and admixed to form the Bronze Age population after 2000 BCE with ~40% ancestry from incoming groups (Fig. 2B and fig. S6).
Y-chromosome turnover was even more pronounced (Fig. 2B), as the lineages common in Copper Age Iberia (I2, G2, and H) were almost completely replaced by one lineage, R1b-M269. These patterns point to a higher contribution of incoming males than females, also supported by a lower proportion of nonlocal ancestry on the X-chromosome (table S14 and fig. S7), a paradigm that can be exemplified by a Bronze Age tomb from Castillejo del Bonete containing a male with Steppe ancestry and a female with ancestry similar to Copper Age Iberians.
For the Iron Age, we document a consistent trend of increased ancestry related to Northern and Central European populations with respect to the preceding Bronze Age (Figs. 1, C and D, and 2B). The increase was 10 to 19% (95% confidence intervals given here and in the percentages that follow) in 15 individuals along the Mediterranean coast where non-Indo-European Iberian languages were spoken; 11 to 31% in two individuals at the Tartessian site of La Angorrilla in the southwest with uncertain language attribution; and 28 to 43% in three individuals at La Hoya in the north where Indo-European Celtiberian languages were likely spoken (fig. S6 and tables S11 and S12).
This trend documents gene flow into Iberia during the Late Bronze Age or Early Iron Age, possibly associated with the introduction of the Urnfield tradition (18). Unlike in Central or Northern Europe, where Steppe ancestry likely marked the introduction of Indo-European languages (12), our results indicate that, in Iberia, increases in Steppe ancestry were not always accompanied by switches to Indo-European languages.
I think it is obvious they are extrapolating the traditional (not that well-known) linguistic picture of Iberia during the Iron Age, believing in continuity of that picture (especially non-Indo-European languages) during the Urnfield period and earlier.
What this data shows is, as expected, the arrival of Celtic languages in Iberia after Bell Beakers and, by extension, in the rest of western Europe. Somewhat surprisingly, this may have happened during the Urnfield period, and not during the La Tène period.
Also important are the precise subclades:
We thus detect three Bronze Age males who belonged to DF27 (154, 155), confirming its presence in Bronze Age Iberia. The other Iberian Bronze Age males could belong to DF27 as well, but the extremely low recovery rate of this SNP in our dataset prevented us to study its true distribution. All the Iberian Bronze Age males with overlapping sequences at R1b-L21 were negative for this mutation. Therefore, we can rule out Britain as a plausible proximate origin since contemporaneous British males are derived for the L21 subtype.
BAL0051 could be assigned to haplogroup I1, while BAL003 carries the C1a1a haplogroup. To the limits of our typing resolution, EN/MN individuals CHA001, CHA003, ELT002 and ELT006 share haplogroup I2a1b, which was also reported for Loschbour  and Motala HG , and other LN and Chalcolithic individuals from Iberia [7, 9], as well as Neolithic Scotland, France, England , and Lithuania . Both C1 and I1/ I2 are considered typical European HG lineages prior to the arrival of farming. Interestingly, CHA002 was assigned to haplogroup R1b-M343, which together with an EN individual from Cova de Els Trocs (R1b1a) confirms the presence of R1b in Western Europe prior to the expansion of steppe pastoralists that established a related male lineage in Bronze Age Europe [3, 6, 9, 13, 19]. The geographical vicinity and contemporaneity of these two sites led us to run genomic kinship analysis in order to rule out any first or second degree of relatedness. Early Neolithic individual FUC003 carries the Y haplogroup G2a2a1, commonly found in other EN males from Neolithic Anatolia , Starçevo, LBK Hungary , Impressa from Croatia and Serbia Neolithic  and Czech Neolithic , but also in MN Croatia  and Chalcolithic Iberia .
Several Iberian scholars have referred to stab-and-drag designs in both Bell-Beaker and Bronze Age ceramics (Maluquer de Motes 1956, 180, 196; Fernández-Posse 1982, 137), although these have not always been correctly appraised. In the 1980s it was finally realized that the sherds retrieved at the Boquique Cave should be dated to the Middle-Late Neolithic (4400-3300 BC), and that the same technique was also widely used in the Late Bronze Age (Fernández-Posse 1982, 147-149). Thus, nowadays it is possible to track this technique in inland Iberia at different moments throughout later prehistory (Alday and Moral 2011, 67). The earliest stab-and-drag motifs (Figure 2.2, 1) are, in fact, older than was initially thought (Fernández-Posse 1982); they actually date to the Early Neolithic (5500-4400 BC), contemporary to the Mediterranean Cardial impressed wares (Alday 2009, 135-137). There are also a few sporadic examples of stab-and-drag motifs among Bell-Beaker pottery (2600-2000 BC), such as the Ciempozuelos-style bowl from Las Carolinas (Madrid) (Figure 2.2, 2a) featuring so-called ‘symbolic’ schematic stags drawn by using this technique (Blasco and Baena 1996, 431, Lám. II; Garrido Pena 2000, 108). It is also possible to recognize this technique in a large Beaker from Molino Sanchón II (Zamora) (Abarquero et al. 2012, 206, fig. 190; Guerra-Doce et al. 2011, 812) (Figure 2.2, 2b) and there are other possible cases (e.g. Montero and Rodríguez 2008, 166, Lám. IX). Finally, the widespread use of this technique occurred in the Late Bronze Age (Figure 2.2, 3a & 3b) from c.1450 BC (e.g. Rodríguez Marcos 2007, 362-364; Abarquero 2005).
Analogies between Bell-Beaker and Bronze Age wares
Several Bell-Beaker styles can be discerned in the Iberian Meseta (e.g. Harrison 1977, 55-67; Garrido Pena 2000; 2014). In this subsection attention will be drawn primarily to the most frequent of these variants, the Ciempozuelos style, although more localised similarities can be recognised between the Beaker impressed-comb style and some early Cogotas I pottery. The Ciempozuelos ware (Delibes 1977; Harrison 1977, 19-20; Blasco 1994; Garrido Pena 2000, 116-126; Rodríguez Marcos 2007, 252-256) was widespread throughout the Meseta between 2600-2000 BC, in the same region subsequently occupied by Cogotas I communities (1800-1150 BC) (Fernández-Posse 1998; Abarquero 2005) (Figure 2.1). There is a wide array of resemblances between both pottery assemblages, a point that has been highlighted since the 1920s (e.g. Almagro Basch 1939, 143-144; Maluquer de Motes 1956, 196; Harrison 1977, 20; Jimeno 1984, 117-118).
The key ornamental traits that define the Ciempozuelos style are also reproduced among Cogotas I ware and are the following:
a) Widespread deployment among the early Cogotas I pottery of the more ubiquitous incised motifs in the Ciempozuelos style: herringbones, spikes and reticulates (Garrido Pena 2000, 119-120, fig. 48, themes 6 and 9; Rodríguez Marcos 2012, 155). During the Middle Bronze Age other less frequent themes are also similar to Bell-Beaker decorations, such as incised triangles filled with lines. Late Bronze Age wares feature the so-called ‘pseudo-Kerbschnitt’ (Rodríguez Marcos 2007, 369) which has striking precedents among Ciempozuelos ware (Harrison 1977, 20; Garrido Pena 2000, 120, fig. 48, theme 12) (Figure 2.3, 1a & 1b).
b) The extensive use of internal rim decoration, almost always deploying chevron motifs. This is ‘a Ciempozuelos leitmotiv’ (Harrison 1977, 20) in the Northern Meseta, where between 30% – 50% of all rims exhibit such a feature (Delibes 1977; Garrido Pena 2000, 163). The decoration of internal rims is even more widespread among Cogotas I vessels (Jimeno 1984; Rodríguez Marcos 2012, 158) (Figure 2.3, 1a).
c) White paste rubbed into the geometric decorations (Delibes 1977; Harrison 1977, 20; Jimeno 1984). Maluquer de Motes (1956, 186) in fact regarded excised and stab-and-drag techniques not as decorations per se, but as a way of anchoring encrusted inlays. He also reported that the bulk of rims in Cogotas I vessels exhibit white accretions (Maluquer de Motes 1956, 192) (Figure 2.3).
In addition, several authors agree on the likeness between the Bell-Beaker impressed-comb style and certain Cogotas I local pottery variants corresponding to its earliest phase (1800-1450 BC) (Garrido Pena 2000, 113-116). This is particularly striking for one micro-style from the western Meseta region, whose ceramics feature numerous impressed-comb motives (e.g. Fabián 2012; Rodríguez Marcos 2012, 158).
The relevance of emulated pottery decorations
 (…) there are grounds for proffering the view that the key creative mechanism responsible for the resemblances between apparently unrelated pottery assemblages was the emulation of standalone and very apparent decorative traits. It may constitute a good case for horizontal cultural transmission predicated upon iconic resemblances between easily imitated formal traits (Knappett 2010). Instead of spontaneous and autonomous innovations, it is far more compelling to regard these decorative features as interlinked and punctuated ‘way stations along the trails of living beings, moving through a world’ (Ingold and Hallam 2007, 8). No creative act can be regarded as really isolated. Instead it ought to be understood as focusing on the nodes in particular fields of associations (Lohnmann 2010, 216).
 Pottery ornamentation in the Cogotas I tradition combined and reinterpreted both local atavistic (e.g. Abarquero 2005, 24-26; Rodríguez Marcos 2007, 357-367) and widespread pan-European ornaments (e.g. Blasco 2001, 225, 2003, 67-68; Abarquero 2012, 98-101). From a semiotic perspective such things transcended large spatio-temporal distances; they were closely associated by iconical shared links in a relational or cognitive space, whereby these entities were co-presented and indirectly recalled and perceived despite being distant (Knappett 2010, 85-86). The locally-rooted biases of these creative quotations can be glimpsed from rare sequences of ceramic productions spanning several generations of potters. For instance, at Majaladares (Borja, Zaragoza) strong analogies arise between Ciempozuelos wares featuring unique decorations in this site and Cogotas I wares from the superimposed layers, exhibiting remarkably similar themes (Harrison 2007, 65-82). Likewise, it is noteworthy that the earliest triangular excisions in Cogotas I wares occurred in the eastern Meseta, where imported Duffaits vessels featuring comparable motifs were circulating from several centuries before.(…)
 There is scope for advocating that these pottery decorations cannot be envisaged as a form of irrelevant or mundane aesthetic garnish for the sake of art. Bronze Age potters drew upon a highly meaningful array of esoteric sources and, in so doing, the vessels might have echoed designs betokening genealogical, mythical or parallel worlds, in a kind of dialectical negotiation between self and other (Taussig 1993). The very involvement of ancestors and spiritual forces in making and embellishing a pot is supported by ethnographic evidence (e.g. Crown 2007, 679; Lohnmann 2010, 222) and this also seems plausible in the case of Cogotas I ceramics. These real or imagined beings might be regarded as inspiring sources of creations, whose role is often to legitimize and guarantee the accuracy of the involved knowledge (Lohnmann 2010, 222). In the same vein, the smearing of colored inlays on certain pots ought to be properly understood beyond an aesthetic action of embellishment, as our own rationale prompts us to assume. (…)
 Furthermore, this pottery tradition needs to be understood as an effective means of socialization and a key resource in the forging of identities. Decorating certain intricate Cogotas I vessels (Figure 2.2, 3b; Figure 2.4, 3) very likely involved an ostentatious difficulty (Robb and Michelaki 2012, 168; Abarquero 2005, 438) and the proficiency displayed in such tasks may have accrued even moral connotations (Hendon 2010, 146-147). Learning to perform some of the pottery decoration discussed here certainly required complex training processes involving both expert potters and mentored apprentices (Crown 2007; Hosfield 2009, 46). Thus, the stab-and-drag technique demanded time-consuming learning as well as careful and thorough execution (Alday 2009, 11-19). Likewise the selection and processing of particular raw materials – mainly bones – to attain the white inlays involved direct observation and hands-on training (Odriozola et al. 2012, 150). (…)
 Finally, the role of the Cogotas I pottery decoration was also deeply rooted in the sphere of social interactions through particular communal practices of exhibition and consumption. The celebration of commensality rituals is very often predicated as a key social practice among these communities (e.g. Harrison 1995, 74; Abarquero 2005, 56; Blanco-González 2014, 453). Potters embodied and replicated non-discursive shared tenets on a routine basis, but by means of these social gatherings and the deployment of such festive services ‘their visual materialisation made them part of the habitus of everybody’ (Chapman and Gaydarska 2007, 182). Bronze Age groups in the Meseta have recently been characterized as scarcely integrated, short-lasting and unstable social units, lacking long-term cultural rules and institutions, restricted to one generation lifespan at the most (Blanco-González 2015). (…)
If we take into account that the earliest Iberian Bell Beakers were I2a, R1b-V88, and G2a, just like previous Chalcolithic and Neolithic Iberians, it cannot get clearer how and when the first Indo-European waves reached Iberia, and thus that the Harrison and Heyd (2007) model of East Bell Beaker expansion was right. Not a single reputable geneticist contests the origin of R1b-L23 subclades in Iberia anymore (see e.g. Heyd, or Lazaridis).
While the Spanish archaeological school will be slow to adapt to genetic finds – since there are many scholars who have supported for years other ways of expansion of the different Bell Beaker motifs, and follow mostly the “pots not people” descriptive Archaeology – , many works like these can be just as well reinterpreted in light of what we already know happened in terms of population movements during this period, and this alone gives a whole new interesting perspective to archaeological finds.
On the previous, non-Indo-European stage of the Iberian Paeninsula, there is also a new paper (behind paywall), showing reasons for inter-regional differences, and thus supporting homogeneity before the arrival of Bell Beakers:
The Chalcolithic period is traditionally defined by the emergence of copper elements and associated to the beginning of defensive-style architecture (Esquivel and Navas 2007). This last characteristic only seems to appear clearly in the southeast of the Iberian Peninsula, with the denominated Millares Culture (e.g. García Sanjuán 2013; Valera et al. 2014). In the rest of the Iberian Peninsula, the Neolithic-Chalcolithic transition is scarcely defined. In fact, it is possible that this transition does not even strictly exist and rather results from the evolution of villages present in the most advanced phases of the Neolithic (e.g. Blasco et al. 2007). This continuity is also perceptible in most of the sepulchral caves over time, where radiocarbon dates show a continued use from the 4th to the 3rd millennium cal B.C. (Fernández-Crespo 2016; Utrilla et al. 2015; Villalba-Mouco et al. 2017). Moreover, it is possible to find some copper materials normally associated with burial contexts as prestigious grave goods (Blasco and Ríos 2010), but not as evidence of a massive replacement of commonly used tools such as flint blades, bone industry, polished stones or pottery without singular characteristics from a unique period (Pérez-Romero et al. 2017). (…)
The human isotope values from both sites portray a quite homogeneous overall diet among humans. This homogeneous pattern of diet based on C3 terrestrial resources seems to be general along the entire Iberian Peninsula during the Late Neolithic and Chalcolithic (e.g. Alt et al. 2016; Díaz-Zorita 2014; Fernández-Crespo et al. 2016; Fontanals-Coll et al. 2015; García-Borja et al. 2013; López-Costas et al. 2015; McClure et al. 2011; Sarasketa-Gartzia et al. 2017; Villalba- Mouco et al. 2017; Salazar-García 2011; Salazar-García et al. 2013b; Salazar-García 2014; Waterman et al. 2016). The reason of this homogeneity could be the consolidated economy based on agriculture and livestock, together with a higher mobility among the different communities and the increase of trade networks, not only in prestigious objects (Schuhmacher and Banerjee 2012) but also in food products. Isotopic analyses in fauna remains could give us more clues about animal trade, as happens in other chronologies (Salazar- García et al. 2017).
In any case, and even if the dietary interpretation does not vary, it is noteworthy to mention that there are significant differences between δ13C human values from Cova de la Guineu and δ13C human values from Cueva de Abauntz (Mann-Whitney test, p = 1.05× 10−12) (Fig. 6). This observed δ13C differences among humans is also present among herbivores (Mann-Whitney test, p = 0.0004), which define the baseline of each ecosystem. This suggests that the observed human difference between sites should not be attributed to diet, but most possibly to the existence of enough environmental differences to be recorded in the collagen δ13C values along the food web. Plants are very sensitive to different environmental factors (altitude, temperature, luminosity or water availability) and their physiological adaptation to its factors can generate a variation in their isotopic values as happens with C3 and C4 adaptations (O’Leary 1981; Ambrose 1991). This spectrum of values has been used to assess several aspects about past environmental conditions when studying the δ13C and δ15N isotopic values of a species with a fixed diet over time (e.g. Stevens et al. 2008; González-Guarda et al. 2017). Moreover, this gradual δ13C and δ15N variation among different environments is very helpful to discriminate altitudinal movements in herbivores with a high precision method based on serial dentine analysis (Tornero et al. 2016b). In our case, results reflect the influence of environment from at least two areas in Iberia (the Western Prepyrenees and the Northeastern coast of Iberia). These differences demand caution when interpreting human diets from different sites that are not contemporary and/or not in a same area, as it is possible that the environmental influence is responsible for changes otherwise attributed to different subsistence patterns and social structures (Fernández-Crespo and Schulting 2017), as has been demonstrated in neighbouring territories (Herrscher and Bras-Goude 2010; Goude and Fontugne 2016).
A manuscript co-authored by Angel Carracedo, from the University of Santiago de Compostela, and (always according to him) pre-accepted in Nature, will offer more insight into the population substructure of Spain, based on autosomal DNA.
Carracedo’s lecture about DNA (in Galician), including his summary of the paper (from december 2017):
Some of the points made in the video:
The study shows a situation parallelling – as expected – the expansion of Spanish Medieval kingdoms during the Reconquista (and subsequent repopulation).
In it, the biggest surprise seems to be the greater substructure found in Galicia, the north-western Spanish territory – greater even than expected by the authors.
As a side note, Galicia shows a great influence from “Moorish” ancestral components, due mainly to the influx from Portugal, which shows more.
It is difficult to judge only from the image and his words, but one could say that there are:
Certain quite old ancestral Galician groups;
then two – also quite old – ancestral Basque groups;
then more recent Galician groups;
and then a common, central Spanish group – including
a wider Asturian-Catalan group, with a western Asturian-Leonese, and an eastern Catalan subgroup;
and a central Castillian-Aragonese group, also with a western Castillian, and an eastern Aragonese subgroup.
We thought that certain parts of the British Isles could show ancestral components related to the old population, although this has not proven exactly right, due to more recent population expansions.
However, this paper might shed light to the controversy surrounding Lusitanian (possibly Gallaico-Lusitanian) as a Pre-Celtic Indo-European group of Iberia, either slightly older as an Italo-Celtic dialect, or potentially from the Bell Beaker expansion, whose genetic imprint might have survived the Roman conquest, which apparently didn’t replace its ancestral population.
Given the presence of a central Spanish group opposed to the other minor groups – and knowing that (at least part of) the Medieval kingdoms should be related to the Occitan region – due to the Celtic expansion, and also potentially later during the Visigothic Kingdom, and the Carolingian Empire – , we can only guess that the other (north-western and Basque) groups are potentially quite old, and reflect prehistoric population structures.
Just speculating here, of course. Another interesting genetic paper to await…
Fernando López-Menchero and I have published our first draft on the North-West Indo-European proto-language. Our contribution concerns mainly phonetics, and namely two of its most controversial aspects: a common process of laryngeal loss and two series of velars for PIE.
There is also an updated linguistic model for the Corded Ware substrate hypothesis, which seeks to explain certain similarities between Germanic and Balto-Slavic, and between Balto-Slavic and Indo-Iranian, and potential isoglosses between the three.
As you probably know, our interest is (and has been for the past 15 years or so, even before our common project) the reconstruction of a North-West Indo-European proto-language, the ancestor of Italo-Celtic, Germanic, and Balto-Slavic. At least since Krahe’s proposal of an Alteuropäische substrate to European hydronymy, some 70 years ago, Indo-Europeanists have been supporting an Old European branch of Proto-Indo-European.
However, dialectal divisions were tentative. Since Oettinger, some 30 years ago, we have a clearer picture of a group of closely related dialects, namely Italo-Celtic, Germanic, and Balto-Slavic. Although the nature of Balto-Slavic is somehow contended (for the few scholars who support an Indo-Slavonic group), the minimalist view holds that at least the substrate language of Baltic and Slavic, Holzer‘s Temematic, was part of the North-West Indo-European group.
A North-West Indo-European (NWIE) proto-language not only solved the controversial question of Pan-European IE hydronymy (clearly of Late Indo-European nature), but also – and more elegantly – the question on the origin of the many fragmentary languages attested in Western Europe, usually attributed to a “Pre-Celtic” or “Pre-Italic” nature depending on their surrounding languages (Venetic has even said to be related to Germanic…).
Described first mainly in terms of lexical isoglosses, the concept of a NWIE language was then gradually and strongly founded in common grammatical features, contributed to mainly by the German, North American, and Spanish schools (as you know, the British or French schools are quite divided on the nature of Proto-Indo-European itself…). Recent archaeological models pioneered by Harrison and Heyd (2007) showed how this might have happened, with Yamna migrants that evolved as the East Bell Beaker group, and their subsequent expansion into most of Europe.
This traditional model of a ‘Corded Ware -> Bell Beaker expansion of NWIE’ which we also followed until recently, never fit well with the known migrations paths from Yamna (into Balkan Early Bronze Age cultures), with the geographic distribution of Old European hydronymy, or with the guesstimates for Late Indo-European and North-West Indo-European. This compelled us to support a break-up of the proto-language further back in time than warranted by models of language change, and it needed certain unlikely cultural diffusion events over huge areas (because no such migration from Yamna to northern Europe has been attested): along the steppe/forest-steppe zone first, for a diffusion from Yamna into Corded Ware cultures, and along the Danube or the Rhine later, for a diffusion of Corded Ware into Bell Beaker. These models were also based on the wrong interpretation of the first radiocarbon dates of Beakers – placing an origin of the Bell Beaker people in Iberia (which has been rejected in Archaeology, and now also in Genetics).
Such a ‘Germano-Balto-Slavic’ group faded in Linguistics long ago, with most Indo-Europeanists preferring to talk about late contacts (viz. Celto-Germanic or Italo-Germanic contacts), and for some there is – if any subgroup at all – a core West Indo-European or Italo-Celto-Germanic group, which may be supported by recent genetic research on Bell Beaker peoples, with the Beaker group of the Netherlands being the key. Our research on the potential language spoken by Corded Ware peoples – most likely related to Uralic, from an Indo-Uralic community from the Pontic-Caspian steppe – can elegantly explain the isoglosses that both European dialects share.