Proto-Tocharian language

Sound changes

Proto-Tocharian underwent extensive phonological changes from Proto-Indo-European, including major vowel developments, consonant simplification, and widespread palatalization.

Vowels

Proto-Tocharian shows radical changes in its vowels from Proto-Indo-European (PIE). Laryngeal e-coloring and vowel lengthening occurs as it does in most other branches, however, length distinctions eventually disappeared. Prior to the loss of length distinction, all pairs of long and short vowels became distinct in quality, and thus have different outcomes. Many pairs of PIE vowels are distinguished in Tocharian only by the occurrence or non-occurrence of palatalization.

Reconstructing the changes between PIE and Proto-Tocharian vowels is fraught with difficulty, and as a result there are a large number of disagreements among different researchers. The basic problems are:

• Tocharian A and B are relatively sparsely attested.
• The extensive mergers of PIE stop consonants lead to many ambiguities in the potential etymologies underlying particular Tocharian words.
• The radical restructuring of the vowel system means that few potential sound changes can be rejected as unreasonable, no matter how unlikely they may look on the surface.
• A large amount of analogical change has occurred in both the nominal and verbal systems, making it difficult to identify which changes are regular.

Historically, the evolution of the Tocharian vowels was the last part of the diachronic phonology to be understood. In 1938, George S. Lane remarked of Tocharian that "the vocalism so far has defied almost every attempt that has been made to bring it to order", and as late as 1945 still asserted: "That the subject [of palatalization] is a confused and difficult one is generally recognized—but so are most of the problems of Tocharian phonology." However, rapid progress towards understanding the evolution of the vocalic system, and with it the phonology as a whole, occurred during the period of approximately 1948–1960, beginning with Sieg and Siegling (1949). By 1960, the system was well-enough understood that Krause and Thomas's seminal work of that year is still considered one of the most important Tocharian grammatical handbooks.

Despite the apparent equivalence between the Tocharian A and B vowel systems, in fact a number of vowels are not cognate between the two varieties, and Proto-Tocharian had a different vowel system from both. For example, Tocharian A a reflects a merger of two Proto-Tocharian vowels that are distinguished in Tocharian B as e and o, while Tocharian B a reflects a stress-based variant of either Proto-Tocharian ā or ä, while Tocharian A preserves original ā and ä regardless of the position of stress.

As a general rule, Tocharian B reflects the Proto-Tocharian vowel system more faithfully than Tocharian A, which includes a number of changes not found in Tocharian B, e.g. monophthongization of diphthongs, loss of all absolutely final vowels, loss of ä in open syllables, and epenthesis of ä to break up difficult clusters (esp. word-finally) that resulted from vowel losses.

The following table describes a typical minimal reconstruction of Late Proto-Tocharian, which includes all vowels that are generally accepted by Tocharian scholars:

The following table describes a "maximal" reconstruction of Proto-Tocharian, following Ringe (1996):

Some of the differences between the "minimal" and "maximal" systems are primarily notational: Ringe's *ǝ = standard *ä, and Ringe (along with many other researchers) reconstruct Proto-Tocharian surface *[i] and *[u] as underlying *äy, *äw (*ǝy, *ǝw in Ringe's notation). However, Ringe reconstructs three vowels *ë, *e, *ẹ in place of the single vowel *e in the minimal system. The primary distinction is between *ë < PIE *o, which is assumed to be a central rather than a front vowel because it does not trigger palatalization, and *e < PIE *ē, which does trigger palatalization. Other than palatalization effects, both vowels are reflected identically in both Tocharian A and B, and hence a number of researchers project the merger back to Proto-Tocharian. However, some umlaut processes are thought to have operated differently on the two vowels, and as a result Ringe (as well as Adams and some other scholars) prefer to distinguish the two in Proto-Tocharian. Ringe's *ẹ vowel, a higher vowel than *e, is fairly rare and appears as i in Tocharian B but e in Tocharian A. This vowel does trigger palatalization, and is thought by Ringe to stem primarily from PIE *oy and from loanwords. In general, Ringe's Proto-Tocharian reconstruction reflects an earlier stage than the one described by many researchers.

Some scholars use a different notation from what is given above: e.g. æ or ë in place of the e of the minimal system, å or ɔ in place of the o of the minimal system, and ǝ in place of ä. /ə/, not represented in the minimal system, can be represented with a or ë.

The palatalized labiovelar approximate w' likely allophonically colored the preceding ä into an /y/ like sound due to the differences in development between Tocharian A and B.

Stress

Proto-Tocharian had phonemic stress, although its position varies depending on the researcher. Many researchers project the Tocharian B stress that is recoverable from ā~a and a~ä alternations back to Proto-Tocharian. For the most part, this stress does not reflect PIE stress. Rather, most bisyllabic words have initial stress, and trisyllabic and longer words usually have stress on the second syllable. A number of multisyllabic words in Tocharian B appear to indicate that more than one syllable was stressed; it is thought that these reflect clitics or affixes that still behaved phonologically as separate words in Proto-Tocharian. Ringe, however, prefers to project the PIE stress unchanged into Proto-Tocharian, and assumes that the radically different system seen in Tocharian B evolved within the separate history of that language.

Consonants

The following table lists the reconstructed phonemes in Proto-Tocharian along with their standard transcription. Because its descendants are written in an alphabet used originally for Sanskrit and its descendants, the transcription of the sounds is directly based on the transcription of the corresponding Sanskrit sounds. The Tocharian alphabet also has letters representing all of the remaining Sanskrit sounds, but these appear only in Sanskrit loanwords and are not thought to have had distinct pronunciations in Tocharian. There is some uncertainty as to actual pronunciation of some of the letters, particularly those representing palatalized obstruents (see below).

1. /n/ is transcribed by two different letters in the Tocharian alphabet depending on position. Based on the corresponding letters in Sanskrit, these are transcribed ṃ (word-finally, including before certain clitics) and n (elsewhere), but ṃ represents /n/, not /m/.
2. The sound written c is thought to correspond to a palatal stop /c/ in Sanskrit. The Tocharian pronunciation /tɕ/ is suggested by the common occurrence of the cluster śc, but the exact pronunciation cannot be determined with certainty.
3. The sound written ṣ corresponds to retroflex sibilant /ʂ/ in Sanskrit, but it seems more likely to have been a palato-alveolar sibilant /ʃ/ (as in English "ship"), because it derives from a palatalized /s/.^{[page needed]}
4. The sound ṅ /ŋ/ occurs only before k, or in some clusters where a k has been deleted between consonants. It is clearly phonemic because sequences nk and ñk also exist (from syncope of a former ä between them).

Phonetically, Proto-Tocharian is a centum Indo-European language, meaning that it merges the palatovelar consonants (*ḱ, *ǵ, *ǵʰ) of Proto Indo-European with the plain velars (*k, *g, *gʰ) rather than palatalizing them to affricates or sibilants. Centum languages are mostly found in western and southern Europe (Greek, Italic, Celtic, Germanic). In that sense, Proto-Tocharian (to some extent like the Greek and the Anatolian languages) seems to have been an isolate in the "satem" (i.e. palatovelar to sibilant) phonetic regions of Indo-European-speaking populations. The discovery of Tocharian languages contributed to doubts that Proto-Indo-European had originally split into western and eastern branches; today, the centum–satem division is not seen as a real familial division.

Unlike in most centum languages, Proto-Tocharian maintained separate outcomes of PIE *kʷ and *ḱw. The latter is still reflected as kw in Tocharian B, e.g. yakwe "horse" < PIE *eḱwos.

Nouns

Proto-Tocharian has completely re-worked the nominal declension system of Proto-Indo-European. The only cases inherited from the proto-language are nominative, genitive, accusative, and vocative (preserved in descendants, but Tocharian A lost the vocative case); in Proto-Tocharian the old accusative is known as the oblique case. In addition to these primary cases, however, each Tocharian language has six cases formed by the addition of an invariant suffix to the oblique case – although the set of six cases is not the same in each language, and the suffixes are largely non-cognate. For instance, the Tocharian B word yakwe, the Tocharian A word yuk < Proto-Tocharian *yä́kwë < PIE *h₁éḱwos, all meaning "horse", are declined as follows:

When referring to humans, the oblique singular of most adjectives and of some nouns is marked in both varieties by an ending -(a)ṃ, which also appears in the secondary cases. An example is eṅkwe (Toch B), oṅk (Toch A) "man", which belongs to the same declension as above, but has oblique singular eṅkweṃ (Toch B), oṅkaṃ (Toch A), and corresponding oblique stems eṅkweṃ- (Toch B), oṅkn- (Toch A) for the secondary cases. This is thought to stem from the generalization of n-stem adjectives as an indication of determinative semantics, seen most prominently in the weak adjective declension in the Germanic languages (where it cooccurs with definite articles and determiners), but also in Latin and Greek n-stem nouns (especially proper names) formed from adjectives, e.g. Latin Catō (genitive Catōnis) literally "the sly one" ^{[citation needed]} < catus "sly", Greek Plátōn literally "the broad-shouldered one" < platús "broad".

Verbs

In contrast, the verb verbal conjugation system is quite conservative. The majority of Proto-Indo-European verbal classes and categories are represented in some manner in Tocharian, although not necessarily with the same function. Some examples: athematic and thematic present tenses, including null-, -y-, -sḱ-, -s-, -n- and -nH- suffixes as well as n-infixes and various laryngeal-ending stems; o-grade and possibly lengthened-grade perfects (although lacking reduplication or augment); sigmatic, reduplicated, thematic and possibly lengthened-grade aorists; optatives; imperatives; and possibly PIE subjunctives.

In addition, most PIE sets of endings are found in some form in Proto-Tocharian (although with significant innovations), including thematic and athematic endings, primary (non-past) and secondary (past) endings, active and mediopassive endings, and perfect endings. Dual endings are still found, although they are rarely attested and generally restricted to the third person. The mediopassive still reflects the distinction between primary -r and secondary -i, effaced in most Indo-European languages. Both root and suffix ablaut is still well-represented, although again with significant innovations.

Tocharian A

• *e and *o merged into a, while *ẹ and *ọ became e and o respectively.
• *a was backed to o under a limited set of environments (#_B, #_ṅkw, #C'_m, ...m_l)
• Labiovelar *kʷ (including kw) lost its labialization in Tocharian A, frequently rounding adjacent vowels (*a, *ä > o, u).
• *wā became o after labial consonants.
• *w' and üw' depalatalization, reverting to w and uw.
• Many developments occurred with consonant clusters containing sibilants. *st became ṣt, medial *ks and *kṣ became ps and pṣ, *nṣ and *ñś simplified to ṣ and ñ, and ns simplified to s.
• The simplification of *ns to s palatalized the preceding vowel. The cluster ñc also palatalized the preceding vowel. These vowel palatalizations are as follows:
  • *a > e
  • *ā > e
  • *ä > i
• Word-final *n was lost, initially nasalizing the preceding vowel. The nasalization was later lost, though not before nasal /ɨ̃/ became i.
• Word-final vowels were lost in multisyllabic words unless preserved through the previously mentioned nasalization. As a result, newly word final *y and *w became vowels after consonants.
• ä was inserted to break up word-final stop clusters (PP#) and word-final consonant-resonant clusters (CR#).
  • Example of the above two changes: PToch *rä́tre (from PIE *h₁rudhros) > *rä́tr > *rä́tär > Toch A rtär.
• *ā was weakened to a when the previous syllable contained e, a, o, or ā. Subsequently, *a then became ä in the same environment when a occurred in the following syllable.
• *ä was lost in open syllables (*rä́tär > rtär).
• *w was lost in between consonants, *w before dental consonants was metathesized and became p (*wD > Dp), and *wä became u after consonants.
• *y after a palatal consonant was assimilated, producing a geminate palatal consonant (*C'y > C'C').
• *t assimilated to c when c followed later in the word (*t…c > c…c).
• Many diphthongs were monothongized before a consonant or word finally:
  • *āi, *ai, *oi > e
  • *āu, *au > o
  • *iy > i
  • *uw > u

Tocharian B

• *a umlauted to ā before ā, after which all remaining *a merged with e.
• Palatalized labials and resonants (*p', *m', and *r') lost their palatalization. Before doing so, *p' and *m' fronted following *ä to i. By contrast, *w' and *üw' became y and iy.
• Word initial glides *yi, *wu, and *wo were deleted, becoming i, u, o respectively. Additionally, *y was lost after *ṣ.
• *ẹ and *ọ became i and o respectively
• As in Tocharian A, inherited *kʷ lost its labialization. However, inherited *kw became kʷ and was preserved as a labiovelar. Before this, *kʷäkʷ colored its vowel to *kʷokʷ (later kok).
• An epenthetic ä was inserted to break up non-initial consonant–resonant clusters unless the preceding vowel was also ä.
• Proto-Tocharian stress was largely retained but underwent systematic reorganization:
  • Stress on ä preferentially shifted to the preceding non-ä vowel, otherwise to the following non-ä vowel.
  • Subsequently, stressed vowels outside the first syllable shifted their stress to the following syllable.
• *ä is lost; unstressed in coda position, between an approximate and a consonant, and before t or s outside the first syllable.
• Conditioned vowel changes before glides (*āy > oy; *eGC > aGC).
• In disyllabic words, stress was ultimately fixed on the first syllable.
• Unstressed *ā became a, while stressed *ä became a.
• Following a vowel, *w was assimilated to a preceding dental consonant, producing a geminate.
• *pn became mn and Intervocalic *mn underwent metathesis to nm.
• An epenthetic t developed between nasals or resonants and following siblants (*NS > NtS; *RS > RtS). Conversely, *t was lost from initial *tk clusters and from *Rtk clusters (*#tk > k; *Rtk > Rk).
• Word-final *s was lost after n.

Vowel development

The following table shows the most basic changes from Proto-Indo-European (PIE) to Proto-Tocharian (PToch) and on to Tocharian B (TB) and Tocharian A (TA), using the notation of the "minimal" system and using a for /ə/:

Notes:

1. A + sign indicates palatalization. When following a consonant, that consonant is palatalized; otherwise, a y appears. Before PIE i, consonants other than dentals are not necessarily palatalized (researchers differ on what exactly happened); this is indicated as (+).
2. PIE u also inserts a w word initially, indicated as (w).
3. A – sign indicates no vowel; this results from deletion of ä in open syllables.
4. Tocharian B reflects Proto-Tocharian central vowels (ä, ā) differently depending on whether they bore stress or not. This is indicated in the table above: stressed ä ā > a ā while unstressed ä ā > ä a (i.e. Tocharian B a reflects either stressed ä or unstressed ā). An additional complication is that unstressed ä is deleted in open syllables.

Citations

Sources