Sanskrit and Tocharian

Of the 3672 entries of the Tocharian A dictionary (Carling and Pinault to appear), 772 lemma have been marked as “from Sanskrit”, which represents 21% of the entire vocabulary (of 1508 nouns, 338 are from Sanskrit, representing 22%). Of these 772 lemma, 39 are marked as “via Middle Indic”, which represents 5% of the words borrowed from Sanskrit. Compared to Sanskrit loans, other source languages are marginal: there are 22 words marked as “from Middle Iranian”, 5 “from Chinese”, 10 “from Uighur”, 10 “from Prakrit”, and 4 “from Pali”.
What does this imply? First, and foremost, of course, that Sanskrit, or rather Buddhist Hybrid Sanskrit, plays a fundamental role in Tocharian literature. “From Sanskrit” means that a word has been borrowed from Classical Sanskrit (Monier Williams 1899) or Buddhist Hybrid Sanskrit (Edgerton 1953, Bechert, Waldschmidt, and Bongard-Levin 1996) with no other change than an adaptation to the morphological system according to the languages’ rules for adapting loans (Krause and Thomas 1960). “From Prakrit” or “from Pali” means that the word can be traced back to a source attested in Pali or Prakrit texts, which apparently is much more unusual than the other way round.
So, what type of changes are we talking about when we define words as “via Middle Indic” instead of just “from Sanskrit”? (Note that the examples below are from Tocharian A: there are also similar patterns in Tocharian B (Carling 2005)). Let us look at a couple of examples.
Some of the words are almost identical to the Sanskrit word, with little change:  A pāruṣak (n.) ‘name of a mythical garden’, via Middle Indic from Sanskrit pāruṣyaka- ‘n. of one of the groves of trāyastriṃśa gods’ (BHSD:343b), as in Pali phārusaka- ‘name of one of Indra's groves’ (PED:478b).  A kās* ‘Kāśa, a species of grass’, via Middle Indic from Sanskrit kāśa- ‘a species of grass’ (MW:280b).  
In other lexemes, there is more far-gone phonological change, which were either taken over from the Middle Indic source word, or alternatively, they took place in Tocharian. This remains unclear. Examples are: A kurkal (n.) ‘bdellium, a medical ingredient’, via Middle Indic from Sanskrit gulgulu- ‘bdellium’ (MW:360b). A klawe (n.m.) ‘die, throw of the die’, via Middle Indic from Sanskrit glaha-, originally ‘throw of the dice’, and individually ‘die’ (MW:374b). A jar (n.m.) ‘topknot’, via Middle Indic from Sanskrit jaṭā- ‘the hair twisted together (as worn by ascetics)’ (MW:408a). A tāpātriś (n.m.) ‘name of a class of gods’, via Middle Indic from Sanskrit trāya(s)-triṃśa- ‘name of a class of gods’, cf. Pali tāvatiṃsa (BHSD:257b).  A patatam (adv.) ‘fortunate, gifted’, via Middle Indic from Sanskrit pradattam, neuter adv. from pradatta- ‘granted, bestowed, gifted’ (MW:679c). A nātäk (n.m.) ‘lord’, via Middle Indic from Sanskrit nāthaka-, derived from Sanskrit nātha- ‘protector, patron, owner, lord’ (MW:534c). This vocabulary, both in Tocharian A and B (which has a larger vocabulary), is very interesting. The lexemes were apparently not borrowed from the literary standard of Prakrit and Pali or from Buddhist Hybrid Sanskrit directly. Rather, they were borrowed from one or several local Indo-Aryan dialects, which became extinct, but which may be part of a general change in Middle Indo-Aryan leading to the dialectal diversity of Modern Indo-Aryan languages.
In addition, the boundaries between Indo-Aryan and Iranian in some of these lexemes are not sharp: the words may have been borrowed from Iranian, but since Indo-Aryan is much better attested (via Classical Sanskrit), an Indo-Aryan source becomes more likely.
 
A systematization of sound changes in these words would likely add knowledge to the evolution of sound changes in Middle Indo-Aryan leading to Modern Indo-Aryan. This will also help us to teas apart Iranian from Indo-Aryan borrowings in Tocharian.

Bechert, Heinz, Ernst Waldschmidt, and Grigorij Maksimovic Bongard-Levin. 1996. Sanskrit-Wörterbuch der buddhistischen Texte aus den Turfan-Funden. Beih. 6, Sanskrit-Texte aus dem buddhistischen Kanon: Neuentdeckungen und Neueditionen, 3. Folge. Göttingen: Vandenhoeck und Ruprecht.
Carling, Gerd. 2005. "Carling, Gerd. Proto-Tocharian, Common Tocharian, and Tocharian – on the value of linguistic connections in a reconstructed language." In Proceedings of the Sixteenth Annual UCLA Indo-European Conference, edited by Karlene Jones-Bley, Martin E. Huld, Angela Vella Volpe and Miriam Robbins Dexter, 47-70. Washington: Institute of Man.
Carling, Gerd, and Georges-Jean Pinault. to appear. A Dictionary and Thesaurus of Tocharian A. Wiesbaden: Harrassowitz.
Edgerton, Franklin. 1953. Buddhist hybrid Sanskrit grammar and dictionary, William Dwight Whitney linguistic series: Yale U.P.; Oxford U.P.
Krause, Wolfgang, and Werner Thomas. 1960. Tocharisches Elementarbuch. B. 1, Grammatik. Heidelberg.
Monier Williams, Monier. 1899. A Sanskrit-English Dictionary : Etymologically and philologically arranged with special Reference to Cognate Indo-European Languages. Oxford: At the Clarendon Press.