Version of 2016-01-26
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The following article refers arguments of the followers of the glottalic theory as well as critique made by defenders of the classic views. Where [GJ] is given, the author of this article is the creator of the described hypothesis.
Professor Charles Barrack will be so kind as to accept my acknowledgements for sending me his works on the glottalic theory.
The classical historical grammar reconstructs three series of stops for the Proto-Indo-European language (PIE):
These three standard series can be marked with the symbols T, D, Dʱ. The third series comprises breathy voiced stops in fact. Such a reconstruction, often termed the standard theory, is based partially on Greek and partially on Sanskrit. In older works the fourth series Tʰ of voiceless aspirates (pʰ, tʰ, ḱʰ, kʰ, kʷʰ) was also considered but finally that idea was given up. The assumption that four series of stops existed in PIE is known today as the neogrammarian model. It arose when Vedic Sanskrit (having such four series) was admitted to be the least changed language when compared to Proto-Indo-European.
However, there also exist other reconstructions of PIE consonantism. The most known of them is so called glottalic theory. Some elements of it were already postulated by Holge Pedersen, André Martinet and Morris Swadesh but the theory in its mature form was formulated in ’70s. Its creators were, independently, the Soviet scholars Tamaz (Thomas) Gamkrelidze and Vyacheslav Ivanov in 1972, as well as the American linguist Paul Hopper in 1973.
It is significant that after the first period of ecstasy the number of followers of the glottalic theory began to decrease, and most linguists reject it today. Various and sometimes considerable modifications of the glottalic theory emerged with time. One of them is the relatively firmly propagated model which has been proposed by Frederik Kortlandt and described in his numeral works, many of which are accessible on his Internet website.
The following table presents development of stops in particular groups of Indo-European languages.
Abbreviations and symbols:
s – series;
language groups: An – Anatolian, To – Tocharian, Gr – Greek, It – Italic, Ce – Celtic, Ge – Germanic, Ar – Armenian, Al – Albanian, BS – Balto-Slavic, Ir – Iranian (with Kafir), In – Indic (with Dardic);
PIE – reconstruction for the Proto-Indo-European language: cl – the classical (standard) model, g1 – the glottalic theory in the version of Gamkrelidze and Ivanov, g2 – the version of Kortlandt.
T: – strong (fortes) voiceless stops in opposition to weak (lenes) ones,
T – voiceless stops,
D – voiced stops,
Tʰ – voiceless aspirates,
Dʱ – voiced aspirated stops,
Tˀ – voiced ejectives (abruptives),
Θ – voiceless spirants,
Ð – voiced spirants.
A similar chart can be found ex. in Barrack’s works [2002:78]. The opposition of force in Anatolian (T: – T) has accepted here after classical reconstructions (Barrack accepts Tʰ – T). The symbol T need not mark weak consonants: it is so in Anatolian and Armenian, but not in ex. Greek (where T is phonologically strong). In Germanic T denotes a voiceless aspirate stop in general, see below.
In Hopper’s version the basical reconstruction of the PIE system of stops was as follows:
And in Gamkrelidze and Ivanov’s version the reconstruction looked as follows:
It was also assumed that sometimes plain voiceless stops p, t, ḱ, k, kʷ used to happen as allophones of voiceless aspirates, and similarly plain voiced stops b, d, ǵ, g, gʷ used to happen together with aspirated voiced stops as their allophonic variants. In other words, according to the glottalic theory the 3 series of stops were Tʰ ~ T, Tˀ, Dʱ ~ D.
The non-aspirated allophones occurred in roots where another aspirate was present because of a rule that prohibited more than one aspirate in the same root. It depended on a dialect which stop lost aspiration: it was the first one in Indic and Greek, and the second one in Italic.
The system of stops as proposed by glottalicists did not result from methods of reconstuction which are used in historical linguistics but from dependencies which can be observed in languages of the world, called typological universals. However, actually it was based on Armenian consonantism. The differences when comparing it to the classical view were that it contained ejective (abruptive) stops (just like some Armenian dialects).
For some time the glottalic theory was enough popular, and even it was treated as the next step in the development of the historical phonetics of Indo-European languages which followed the laryngeal theory. But it appeared with time that many arguments of glottalicists are easy to refute, and the theory itself must have been strongly modified under pressure of facts.
Below we will present various arguments of followers of the glottalic theory, as well as their detailed analysis.
It was stated that the putative inventory of stops in PIE, consisting of series of voiceless, voiced and voiced aspirated (breathy voiced) stops, is not plausible as linguistic typology does not know examples of similar systems. On the other hand the system of stops proposed by the glottalic theory is as if common among the languages of the world.
In fact Roman Jakobson was wrong when asserting that no language is known which would have a system of stops like the one postulated for PIE. Actually, there are few languages which have voiced aspirated stops but no voiceless aspirates. Robert Blust even showed that a system of voiceless, plain voiced and voiced aspirated stops exists in Kelabit, a language of Borneo. Which is more, Madurese, another Austronesian language, used on Java and the Madura island, according to the original and detailed description of Kiliaan, also contains such a system of stops, even if next the voiced aspirated stops (Dʱ) were described erroneously as voiceless [Barrack 2003b:2]. Thus Jakobson’s argument is a simple urban legend, even if it is true that the standard reconstruction contains a typological rarity.
Nevertheless, one should have in mind that the system proposed by the glottalic theory is not any better in this respect. One can even say that it remains even more implausible. Indeed, the basical Hopper’s version (T, Tˀ, D) is typologically well-founded but it does not explain the existence of voiced aspirated or their traces in IE languages. Because of this, in order to explain known facts from various languages, Gamkrelidze and Ivanov asserted that the 3rd series of stops contained plain voiced and aspirated voiced stops as allophonic variants: D ~ Dʱ. Even this single fact would be a typological oddity.
Which is more, basically there is not an instance of existing ejective consonants together with aspirated voiced stops in languages of the world. Only in one of Khoisan languages (!Xũ) a single voiced aspirated phoneme /gʱ/ has been found together with a series of ejective stops. This language contains 6 series of pulmonic stops (completely differently than PIE according to glottalicists) and is a typological rarity in many aspects.
Early reconstructions of the Proto-Indo-European language slavishly copied structures known in Sanskrit, which was acknowledged to be the most conservative and the less distant from the protolanguage. Among others, existence of 4 series of stops: T, Tʰ, D, Dʱ was assumed in PIE, just like in Sanskrit. Existence of the Tʰ series has not been confirmed ultimately: Sanskrit voiceless aspirates come mainly from PIE sequences of a voiceless and a laryngeal, and their counterparts in other IE languages are, as a rule, plain voiceless stops. The voiceless aspirate series was removed from the reconstruction of the protolanguage consonantism, but the voiced aspirated (breathy voiced) consonants remained in it, causing typological problems described above.
However, the objection of copying Sanskrit structures slavishly was recognized as still valid. Particularly, it concerned distinguishing of series of voiced and voiced aspirated stops (D : Dʱ). Actually this kind of opposition occurs only in Indic, from among all IE languages.
This argument does not seem to be too strong. The following argumentation is totally wrong: if some elements of the reconstruction that were based on Sanskrit appeared inapt, then basing on this language is a mistake in general. It is not so, and thus we should not reject Sanskrit data.
The next argument of glottalicists is again of a typological nature. Namely, it is pointed out that if a voiced stop is absent in a phoneme inventory, it would normally be the velar g (or uvular ɢ) that is missing. On the other hand, if a voiceless stop is missing in the system, the labial p is the most likely candidate. And similarly pˀ is cross-linguistically a much rarer sound than the other ejectives.
The labial consonant of the 2nd series, reconstructed as b in the standard theory, and as pˀ in the glottalic theory, was probably totally absent in PIE. Thus the glottalic proposal would be close to the typological universal.
The present argument is inapt as a whole, and glottalicists’ statements apear simple urban legends once again. Namely, Maddieson did calculations on a representative sample of world’s languages, and stated that more than 10% contain /pˀ/. And if we limit ourselves to languages with any ejective consonants, the percentage will be more than 60% [Barrack 2002:81]. In other words, if PIE had indeed contained ejective stops, we should have assumed on the base of statistics that it had also contained the labial ejective stop.
The next argument of glottalicists is the fact that no IE root in the standard reconstruction contains two plain voiced stops. The lack of the roots of the type *deg- cannot be explained in any way because it is not known what factor would prevent coexistence of two voiced stops.
On the ground of the glottalic theory these roots would have the structure of the type *tˀekˀ-, thus they would have two ejective consonants. The lack of them in PIE would have typological explanation again: roots with two ejectives as if do not occur in languages in the world [Hopper 1973].
Not only roots of the type *deg- but also roots which contain both voiceless and voiced aspirated stops, i.e. roots of the types *tegʱ- i *dʱek-, are absent in the classic reconstruction. The types *degʱ-, *dʱeg- are rare. Hence only the types *tek-, *teg-, *dek-, *dʱegʱ- are frequent. These constraints are typologically odd and cannot be explained in terms of assimilation or dissimilation assuming that both plain and aspirated voiced stops ought to behave identically in these processes. However, if the plain voiced stops were not voiced but abruptive, the voiced aspirated stops were the only voiced stops. In order to explain the absence of the types *tegʱ- i *dʱek-, Hopper formulated a constraint that two nonglottalic stops in one roots must agree in voicing. And because the ejective stops are outside the opposition of voicing, they were at least partially excluded from the constraint.
The argument of glottalicists seems to be strong apparently but a deeper analysis bears doubts again. Namely, the glottalic theory attempts to explain the absence of roots of the type *deg- (basing on universals), but it is not engaged at all in an explanation of the absence of roots of the types *tegʱ- i *dʱek-. The statement that voiced stops do not occur with voiceless stops is not an explanation but a description of an observation rather. In the same time several explanations of these observations were proposed on the base of the classical theory.
First of all, it was noticed [Erhart 1982] that the total frequency of plain voiced and aspirated voiced stops is almost the same as the frequency of voiceless stops. Thus it was assumed that only two series of stops existed in the earliest phase of the protolanguage, and only next the 2nd series split into plain voiced and aspirated voiced. Then the four possible original types of roots which contained two stops developed as follows:
|phase I||phase II|
In the reconstruction of the phase I, the symbols T, K denote stops of the first series (voiceless), the symbols D, G – stops of the second series (voiced), and A is a symbol of a vowel.
This hypothesis explains the absence of roots of the types *deg- (instead of them we have *dʱegʱ-), *tegʱ- (instead of them: *teg-) and *dʱek- (instead of them: *dek-), as well as the rarity of the types *degʱ- and *dʱeg- (which should not be present at all). However, it has two crucial faults which vote for rejecting it:
Absence of roots of the types *tegʱ- and *dʱek- can also be explained on the ground of the classical theory – paradoxically – when applying Gamkrelidze and Ivanov’s supposition on the prohibition of existence of two aspirates in the same root.
In order to do it, we should suppose that the 1st series of stops really contained voiceless aspirates originally, while rejecting all suppositions on ejective articulation of the 2nd series naturally (thus instead of the classical system *t – *d – *dʱ we should reconstruct *tʰ – *d – *dʱ at least for the older phase). On a certain stage of the development of the IE protolanguage a loss of aspiration of the voiced stop took place in original roots of the types *tʰegʱ- i *dʱekʰ-, and as a result the voiced aspirated stops went from the 3rd series to the 2nd series (naturally under the condition that it contained voiced stops of the type *d and not ejectives of the type *tˀ). In the stage which is presented in standard reconstructions of PIE, the aspiration by voiceless stops had declined in all positions, at least in most IE dialects (ex. not necessarily in Proto-Germanic). And finally in particular dialects the aspiration used to decline in roots with two voiced aspirated stops:
|phase I||phase II||phase III||phase IV|
We are not sure whether stops of the 1st series were aspirated for real, but we know for sure that the presence of two aspirates were not allowed actually. In addition, in Indic and Italic what declined was aspiration of voiced (see the chart) whereas in Greek it was aspiration of voiceless (already after devoicing of old voiced aspirated stops).
The next hypothesis [Barrack 2002:81nn] calls observations of glottalicists in question. The starting point is the fact that roots of the *deg- type are however present in Indo-European reconstructions, even if they occur exceptionally. Examples (partially after Barrack, partially own ones) are *bed- ‘to swell’, extended to *bdel- ‘to suck’, *ǵab- ‘to look out, to look for’ (cf. Russ. zabota ‘a care, worry’, Eng. keep), *deg- ‘to touch’ (cf. Eng., known also from Toch., here also perhaps Lat. digitus ‘finger, toe’), *gad- ‘to speak’ (cf. Polish gadać ‘to talk’, also known from Indic). Incidentally, part of these roots contains *b, as if absent in PIE.
As an analysis of the PIE lexicon shows, stops of the 2nd series (D in the standard theory, Tˀ after glottalicists) were generally rare (hence the above described Erhart’s hypothesis). In Pokorny’s dictionary only 187 roots of the total number of 2027 begin with a “glottal” stop (i.e. a voiced nonaspirated one), and 70 roots end with such a consonant. So, the probability of existence of a root which begins with D and ends with D, in the same time, equals but 0,32% (this is the result of the multiplication of probabilities: 187/2027 × 70/2027, expressed as percentage). The expected quantity of roots of the type under question would be 6 or 7, and it is actually less because a root cannot begin and end with the same consonant. This result agrees enough well with reconstructions, which implies that another glottalicists’ argument is not of an important value.
In the contemporary formulation by Dybo , Winter’s Rule (wrongly termed “law”) says that Indo-European short vowels, diphthongs and sonants in the development of the Balto-Slavic became lengthened before an original stop of the second series (D), and received the acuted intonation, i.e. the same like original groups of a vowel plus a laryngeal. The third series (Dʱ) did not cause the lengthening. Examples:
According to Lachmann’s Rule (“Law”) short vowels in Italic lengthened before Proto-Indo-European voiced stops (D) which were followed by a voiceless stop. Examples from Latin:
The 1st and 3rd series (voiceless and voiced aspirated) stops did not cause lengthening, ex.:
The glottalic theory is believed to explain the mechanism behind both rules. The stops of the 2nd series may have been preglottalized at least in Italic and Balto-Slavic, or the former ejectives became preglottalized before losing their glottalization and becoming voiced. Their preglottalization could drop and lengthen preceding vowels in some phonetic environments. This assumption is typologically correct as a similar phenomenon can be observed, among others, in Quileute. In that language the sequences like akˀa ~ aʔkˀa ~ ākˀa, are in free variation.
Opponents of the glottalic theory notice that both Winter’s Rule and Lachmann’s Rule are controversional as they do not seem to be exceptionless (so, they are not phonetic rules in Neogrammarian sense). Some exceptions have been explained while some have not. Some even believe that both rules are artificial, and all the examples should be explained with the help of analogy or other factors.
Thus, Winter’s Rule does not occur before sD, Ds, Dr, Dn, ex. Pol. dobry < *dhabro- (cf. Germ. tapfer ‘brave, bald’ < ‘good’, Lat. faber ‘craftsman’), Pol. dno < *dhub-no- (cf. deep). But there are also other exceptions, like Pol. woda < *wod- ‘water’, stóg < *stog- ‘stack’, or pod < *pod- ‘under’, for which only individual and not always convincible explanations exist (e.g. for stóg, notice the geminate in stack, which is also unexplained).
There also exist some other instances of lenghtening in Balto-Slavic. One of them is seen in the Slavic root *sěk- < *sēk- ‘cut, mow, hack, slash’ (Pol. siec), cf. Lith. į̀sekti, Lat. secō with short e. Dybo has described a lengthening which occurred before an original Dʱn group, which is astonishing, because original Dn groups did not cause lengthening. Examples:
Lachmann’s Rule is not exceptionless, either. It does not function in derivationally isolated forms, like:
as well as in a number of other instances, like:
In the last example two verbs have probably merged, *strig- ‘strip off’ (cf. OE strīcan ‘to brush’, Pol. strzyc ‘to shear, to mow’) and *stregh- ‘tighten’ (cf. OE strengan ‘to attach’), and the “exceptional” form without lengthening comes from the latter. There is also a view that high vowels were more immune to lengthening, hence hesitations in results. On the other hand, the long vowel in ēmptus < *em-to- (cf. emō ‘take, buy’) is unexplained.
Validity of Lachmann’s Rule is undermined by sporadic instances of developing of a geminate with contemporary shortening of the preceding vowel, ex. cippus ‘boundary stone’ < *ceipos (acc. ceipom testified), Juppiter < Jūpiter, littera < leitera (testified in 122 BC), mittō ‘send’ in view of meit- in other Italic languages (< PIE *meitH2-), Varrō together with vārus ‘bandy-legged’.
And even if we assented to the rules to be valid, they would not be a strong evidence for glottalic nature of the 2nd series stops. As it is commonly known, vowels are pronounced longer before a voiced consonant. It can be heard in English, when comparing pairs like bat and bad – the vowel in the latter word is perceptibly longer than in the former. So, if the 2nd series of stops contained voiced consonants, just like the standard theory states, they can have lengthened the preceding vowel without the need of any glottalization.
At the same time, the 3rd series stops did not lengthen preceding vowels even if, as experimental investigations have shown, voiced aspirated stops cause even more lengthening than plain voiced stops. It happened so perhaps because they were not fully voiced at that time. It is noticeable that at least in Italic the former breathy voiced stops became voiceless fricatives. The assumption that a similar process occurred in Balto-Slavic is speculative but not excluded.
Another explanation can be found, though. The original short vowels in Balto-Slavic behaved before D just like before laryngeals which were a kind of aspiration or fricative consonants rather than glottalic stops. Typological investigation shows that both classes of sounds cause opposing results on adjacent vowels. The putative glottalic element of the 2nd series stops operated in the same way as a laryngeal, causing the acute intonation, so it had to be fricative as well. In other words, the 2nd series stops operated like HD groups and not like ʔD groups (as they have often been groundlessly reconstructed recently), i.e. they were preaspirated rather than preglottalized. And even if the origin of that putative preaspiration has not been explained in details yet, it is possible that it had something to do with the changes of the system of stops in Germanic which is a result of the phonological process of forcing.
It is worth noticing that also Germanic voiceless stops, which have come (according to the standard theory) from Indo-European plain voiced stops as the result of the first Germanic consonantal shift, are often preaspirated when not word-initial. So, the putative preaspiration of the 2nd series stops may have been the areal feature of early Germanic and Balto-Slavic dialects. The preaspiration seems to have been really voiceless (hD). In Balto-Slavic it caused the lengthening of the preceding vowel and its rising intonation, and then disappeared. When in Germanic the original voiceless stops became fricative as a result of forcing, preaspirated voiced stops became voiceless, which was a kind of assimilation.
Finally, one more objection can be added to the glottalic explanation of Winter’s Rule and Lachmann’s Rule. Namely, in order to fully explain differences in development of the 2nd series stops, it would had to be assumed that the postulated change of Tˀ into D, typologically uncommon, must have occurred independently in each branch, after the split of the common IE language into dialects. Such parallel developments leading to identical but independent results would be an astonishing coincidence.
As it can be seen from the above analysis, glottalicists’ arguments are not serious. Some of them are of seeming character, others point at problems which can be explained on the basis of the classical theory, often better than when accepting assumptions of the glottalic theory. Moreover there exist facts which cannot be explained by the glottalic theory at all.
As it was mentioned above, the glottalic theory has not been formulated on the base of comparative methods of historical linguistics but rather on the base of typological, and even statistic considerations. And even if some glottalicists claim otherwise, their claims overshoot the truth.
Namely, they are of the opinion that the base for the reconstruction is the similarity of system of stops in Armenian and Germanic. Actually there exists a very important difference between them: voiceless aspirated Tʰ stops have developed of the first series in Armenian while of the second series in Germanic. As a consequence, Armenian voiceless non-aspirated stops T correspond to Germanic voiceless aspirated stops Tʰ.
This fact is totally omitted or distorted by glottalicists. For instance, they try to “prove” that Germanic voiceless stops are not aspirated at all. In the same time the truth is that aspiration was and is common in all Germanic languages. It is meaningless that in English aspirated stops occur mainly before a stressed vowel, unless the spirant s stands before the stop in addition. It is so because other Germanic languages have less limitations of this kind. In particular, the change of old voiceless stops into affricates or spirants in High German (called the second consonant shift) proves that strong aspiration must have accompanied voiceless stops regardless on stress of the following vowel.
In any case, there is no direct evidence for the glottalic reconstruction, and even if it is not required unconditionally (for instance the classical theory has no direct evidence for gʷʱ – the labiovelar voiced aspirated stop), one cannot say that any indirect indications occur, either. These are not typological universals, which are seldom absolute and exceptionless. Such an approach is methodologically suspicious, and it may even be considered to be a methodological error.
The glottalic theory has a problem to explain how the stop systems of particular IE dialects were derived from the system existing in the parent language.
In the classical theory all IE languages have been divided into 2 groups according to development of palatovelar consonants ḱ, ǵ, ǵʱ. In the first group plain velars k, g, gʱ occur today while affricates or spirants occur in the second group (ex. ¶, j, h in Sanskrit, s, z in Slavic). These groups have been termed kentum and satəm, after names of the numeral 100 in Old Latin and Avestan.
For glottalicists the division of IE languages into two groups taihun and decem is more important. These terms were created by Hopper in 1981 from names of the numeral 10 in Gothic and Latin. The old ejective tˀ in taihun languages (Anatolian, Tocharian, Germanic and Armenian) preserves as the voiceless t while as the voiced d in decem languages (all the others).
In Tocharian all the old system collapsed and all three series merged into one. In Anatolian a binary opposition of strength (fortis – lenis, T: – T) arose in the place of the old ternary opposition. Similarly, a typologically frequent binary opposition of voicing (T – D) developed in Celtic, Albanian, Balto-Slavic and Iranian (and perhaps also in Ancient Macedonian). In Indic the old system preserved as a whole but the voiceless aspirate series was added for more symmetry and for more stability. Greek and Italic devoiced the voiced aspirate series to a more common aspirate voiceless one. Finally, chain shifts of all three series happened in Germanic and Armenian.
If PIE had a typologically unstable system, like the classical T – D – Dʱ, then it might be expected to evolve into different more typical systems in the various daughter languages, which is what one finds in real. But if PIE had a typologically common and thus stable system, which is postulated by glottalicists (groundlessly), it might be expected to have been preserved in at least some of the daughter languages, which is not the case: no IE language preserves putative abruptive consonants. Moreover it should be explained for what reason that stable system suffered multidirectional changes. The glottalic theory does not give the needed explanation.
There exist several trials to defend the glottal theory against this.
If PIE had not true ejective consonants in its inventory but ex. preglottalized ones, the system might be less stable and that is why it evolved in daughter languages.
Even stable systems change, and objections arising from theoretical considerations cannot overturn a reconstruction deduced by comparing the evidence of the daughter languages.
However it is problematic whether the glottalic theory delivers a reconstruction arising from comparing testified forms. Statistic arguments are used instead, which are based on misinterpretations in addition.
In order to explain the observed changes of the putative stop system in all groups of Indo-European languages, followers of the glottalic theory assume that the changes were a result of the influence of the substratum languages.
However, such an explanation does not allow us to understand why the influence was to be the weakest on periphery, in taihun languages, so for sure in the Germanic and Tocharian groups at least. According to the glottalic model these groups (together with Armenian and Anatolian) should be changed the least.
An idea has also appeared that the glottalic theory describes an older stage of PIE, which preceded the traditional reconstruction.
Such a solution is nothing more but a glottalicists’ honour trial to retreat of the postulated theses. It is so because the solution means to agree that, first, the Germanic and the Armenian systems have developed independently from the stage which has been postulated by the standard theory for a long time now, and as a result the division into the taihun and decem languages (see below for explanation of these terms) is completely groundless. Second, because of it, the idea of a primitive character of the taihun languages leads to the removing of the rest of bases for applying comparative methods from the glottalic theory and it also leads to necessity of basing on statistics and language universals exclusively. Third, the admitting that the T – D – Dʱ system of stop consonants existed in the late common Indo-European epoch despite of all, cancels all the arguments which vote for existing of a “glottalic element” at the 2nd series of the IE stop consonants, such as Winter’s rule, Lachmann’s rule, or supposed traces of preglottalization in Germanic languages. And last, the postulating of existence of the glottalic system which preceded the stadard one requires external, Nostratic data reference, which is not succeeded too much, as well, see below.
In five groups of Indo-European languages (Anatolian, Celtic, Albanian, Balto-Slavic, Iranian) identification of the series D with Dʱ took place, with the series T preserved distinct. In the same time only the series T with D or only T with Dʱ did not mix together in any group (in Tocharian all three series identified). The facility of merging of the 2nd and the 3rd series may be an argument for that they differed with only one distinctive feature (aspiration).
It is true that stops of the 2nd and the 3rd series had lower frequency than those of the 1st series, and thanks to it their opposition was less loaded functionally. But one should doubt that it was a sufficient reason of the facility of their mixing.
According to the traditional conception, during their development some IE languages underwent the process called the consonantal shift – Lautverscheibung. Mainly Germanic and Armenian belong to this group. Among others, on the place of putative IE voiced stops, voiceless stops occur in both instances.
The glottalic theory inverts the situation totally. According to it the state in Germanic and Armenian is original (or close to original in any case), whereas the actual shift took place in those language groups where we have voiced stops on the place of ejective stops today, that is in ex. Indo-Iranian, Balto-Slavic, Italic or Greek.
The cradle of Indo-Europeans should be searched for in areas where relatively least changed languages occur today. The other languages are said to have changed during migration from that area and taking new territories. Thus the differentiation model basing on the glottalic theory is completely different that the one elaborated for the classical theory. Glottalicists search for the IE homeland mostly in Armenia, whereas the traditional view most often points at Ukrainian and Russian steppes.
The glottalic theory “enjoyed a not insignificant following for a time, and still has adherents; but it has been rejected by most Indo-Europeanists” [Fortson 2004:54]. Recently Bomhard tries to support the glottalic theory in his controversial version of the Nostratic theory.