The laryngeal theory is a widely accepted scientific theory in historical linguistics positing that the Proto-Indo-European (PIE) language included a series of consonants that left no direct consonantal descendants in languages outside of the Anatolian branch. It was first proposed by the Swiss linguist Ferdinand de Saussure in 1879 to explain apparent irregularities in morphophonological patterns in daughter languages. The theory allowed for a better reconstruction of PIE ablaut and root; however, at the time there was no direct evidence of the proposed sounds in any of the daughter languages. This changed in 1927 when a Polish linguist, Jerzy Kuryłowicz, discovered that a sound transcribed as in the newly deciphered ancient Indo-European Hittite language appears in many of the places that the laryngeal theory predicted.
Subsequent scholarly work has established a set of rules by which an increasing number of reflexes in daughter languages may be derived from PIE roots. The number of explanations thus achieved and the simplicity of the postulated system have led to widespread acceptance of the theory.
Conversion from consonants to vowels The reconstructed sounds are traditionally called "laryngeals" and are known to have been consonants, most likely fricatives; however, their exact place of articulation is debated. In its most widely accepted version, the theory posits three laryngeal phonemes in PIE. They are represented abstractly as:
(also written , , or , , , among other notations).
Aside from some direct consonantal reflexes in the Anatolian branch, in all branches, through regular sound changes, the laryngeals were turned into vowels or were lost entirely, influencing the place of articulation or length of neighbouring vowels.
History
The beginnings of the theory were proposed by Ferdinand de Saussure in his 1879 monograph ('A Dissertation on the Primitive System of Vowels in the Indo-European Languages'). In it, he argued that unknown phonemes – called ('sonantic coefficients') – were elided in certain ablauting forms, giving rise to long vowels. These phonemes were such that when they abutted the preceding vowel, they were functionally identical to diphthongs or vowel–sonorant strings.
In the course of his analysis, Saussure proposed that what had then been reconstructed as long vowels and , alternating with , was an ordinary type of PIE ablaut. That is, it was an alternation between e grade and zero grade like in "regular" ablaut (further explanations below), but followed by a previously unidentified element. This element accounted for both the changed vowel colour and the lengthening (short becoming long or ).
So, rather than reconstructing , , and as others had done before, Saussure proposed alternating with and with , where and represented the unidentified elements. Saussure called them simply , which was the term for what are now in English more usually called resonants; that is, the six elements present in PIE which can be either consonants (non-syllabic) or vowels (syllabic) depending on the sounds they are adjacent to: , , , , , and .
These views were accepted by a few scholars, in particular Hermann Möller, who added important elements to the theory. Saussure's observations, however, did not achieve any general currency, as they were still too abstract and had little direct evidence to back them up.
This changed when Hittite was discovered and deciphered in the early 20th century. Hittite phonology included two sounds written with symbols from the Akkadian syllabary conventionally transcribed as , as in 'I put, am putting'. This consonant did not appear to be related to any of the consonants then reconstructed for PIE, and various unsatisfactory proposals were made to explain this consonant in terms of the PIE consonant system as it had then been reconstructed.
It remained for Jerzy Kuryłowicz to propose that these sounds lined up with Saussure's conjectures. He suggested that the unknown consonant of Hittite was, in fact, a direct reflex of the that Saussure had proposed.
Their appearance explained some other matters as well. As an example, most verb roots were reconstructed with both initial and final consonants, but some were instead reconstructed with no final consonant; the latter always bore a long vowel, never short, as in "give". The newly reconstructed laryngeals allowed linguists to decompose this further into . This not only accounted for the patterns of alternation more economically than before (by requiring fewer types of ablaut) but also brought the structure of these roots into line with the basic PIE pattern which required roots to begin and end with a consonant.
The lateness of the discovery of these sounds by Indo-Europeanists is largely because Hittite and the other Anatolian languages are the only Indo-European languages for which at least some are attested directly and consistently as consonantal sounds. Otherwise, their presence is to be inferred mostly through the effects they have on neighboring sounds and on patterns of alternation that they participate in. When a laryngeal is attested directly, it is usually as a special type of vowel and not as a consonant, best exemplified in Greek where syllabic laryngeals (when they appeared next to only consonants) developed as such: > e, > a, and > o.
Varieties of laryngeals There are many variations of the laryngeal theory. Some scholars, such as Oswald Szemerényi, reconstruct just one laryngeal. Some follow Jaan Puhvel's reconstruction of eight or more.
Basic laryngeal set Most scholars work with a basic three:
, the neutral laryngeal , the a-colouring laryngeal , the o-colouring laryngeal
Additional laryngeals
Some scholars suggest the existence of a fourth consonant, , which differs from in not being reflected as Anatolian but being reflected, to the exclusion of all other laryngeals, as Albanian h when word-initial before an originally stressed vowel.
E.g. PIE 'testicle' yields Albanian 'testicle' but Hittite 'testicle' whereas PIE 'bear' yields Albanian 'bear' but Hittite (=/hartka-/) 'cultic official, bear-person'.
When there is an uncertainty whether the laryngeal is or , the symbol may be used.
doublet Another such theory, but much less generally accepted, is Winfred P. Lehmann's view, based on inconsistent reflexes in Hittite, that was two separate sounds. (He assumed that one was a glottal stop and the other a glottal fricative.)
Direct evidence for laryngeals Some direct evidence for laryngeal consonants comes from Anatolian. In PIE is a fairly rare sound, and in an uncommonly large number of good etymologies, it is word-initial. Thus PIE (traditional) 'in front of and facing' > Greek 'against' Latin 'in front of, before' Sanskrit 'near; in the presence of'.
But in Hittite there is the noun 'front, face', with various derivatives ( 'first', and so on), pointing to a PIE root-noun 'face' (of which would be the locative singular).
However, it does not follow that all reconstructed forms with initial should automatically be rewritten .
Similarly, the traditional PIE reconstruction for 'sheep' is (a y-stem, not an i-stem) whence Sanskrit , Latin , Greek . But Luwian has , indicating instead the reconstruction .
Lyco-Carian chain shift In the Anatolian languages Lycian and Carian, there was a chain shift such that > k > c. In other words, PIE is reflected as in these languages, and PIE as . Alwin Kloekhorst takes this as evidence that PIE originally had a value of , but Martin Joachim Kümmel is skeptical of Kloekhorst's hypothesis and prefers to model the laryngeals as fricatives.
Pronunciation Considerable debate still surrounds the pronunciation of the laryngeals and various arguments have been given to pinpoint their exact place of articulation. According to the linguist Donald Ringe, it can be concluded with great certainty that all the laryngeals were obstruents, as they abide by the known rules of Proto-Indo-European obstruent syllabification. Further evidence regarding the pronunciation of the laryngeals may derive from their effects on adjacent phonemes. The evidence from Hittite and Uralic is sufficient to conclude that these sounds were guttural, pronounced rather back in the vocal tract. The same evidence is also consistent with the assumption that they were fricative sounds (as opposed to approximants or stops), an assumption that is strongly supported by the behaviour of laryngeals in consonant clusters, which is comparable to that of the coronal fricative .
Rasmussen suggested a consonantal realization for as the voiceless glottal fricative with a syllabic allophone (mid central unrounded vowel).This is supported by the closeness of to (with which it combines in Greek), its failure (unlike and ) to create an auxiliary vowel in Greek and Tocharian when it occurs between a semivowel and a consonant, and the typological likelihood of an given the presence of aspirated consonants in PIE.
Winfred Lehmann theorized, based on inconsistent reflexes in Hittite, that there were two sounds: a glottal stop and an h sound as in English hat. Robert S. P. Beekes suggested that is always a glottal stop .
Alwin Kloekhorst argued that the Hieroglyphic Luwian sign no. 19 (, conventionally transcribed ) stood for (distinct from , sign no. 450: ) and represents the reflex of ; this would support the hypothesis that was, at least in some cases, . Later, Kloekhorst claimed that also Hittite preserves PIE as a glottal stop , visible in words like Hittite 'he is' < PIE , where an extra initial vowel sign (plene spelling) is used. This hypothesis has been met with serious criticism; e.g., from Elisabeth Rieken, Craig Melchert, and Mark Weeden.
Zsolt Simon supported Kloekhorst's thesis by suggesting that plene spelling in Cuneiform Luwian can be explained in a similar way. Additionally, Simon's 2013 article revises the Hieroglyphic Luwian evidence and concludes that although some details of Kloekhorst's arguments could not be maintained, his theory can be confirmed.
An idea occasionally advanced that the laryngeals were dorsal fricatives corresponding directly to the three traditionally reconstructed series of dorsal stops (palatal, velar, and labiovelar; i.e., that the laryngeals , , and are more accurately written , , and respectively) suggests a further possibility, a palatal fricative .
From what is known of such phonetic conditioning in contemporary languages, notably Semitic languages, (the a-colouring laryngeal) could have been a pharyngeal fricative such as and . Pharyngeal consonants (like heth in the Semitic abjads) often cause a-colouring in the Semitic languages.
Uvular fricatives may also colour vowels; thus, is also a noteworthy candidate. Weiss suggests that this was the case in Proto-Indo-European proper, and that a shift from uvular into pharyngeal may have been a common innovation of the non-Anatolian languages (before the consonant's eventual loss). Rasmussen suggested a consonantal realization for as a voiceless velar fricative , with a syllabic allophone , i.e. a near-open central vowel.
Kloekhorst proposes, based on evidence from Anatolian languages, that was originally a geminate uvular stop (he also holds the view that the traditionally voiceless stops of PIE were in fact geminate, as in Hittite), although he judges it plausible that already in PIE it had a fricative allophone.
Likewise it is generally assumed that was rounded (labialized) due to its o-colouring effects. It is often taken to have been voiced based on the perfect form from the root 'drink' and Cowgill's law in Proto-Germanic (PIE → PPGmc → PGmc , "us two"). Rasmussen chose a consonantal realization for as a voiced labialized velar fricative , with a syllabic allophone , i.e. a close-mid central rounded vowel. Kümmel instead suggests .
Kloekhorst reconstructs as the basic value, which in his view would be the labialized counterpart to (see above).