Resources

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A good textbook for the Sanskrit language:

Coulson, Michael. 1976. Sanskrit. An Introduction to the Classical Language. Teach Yourself Books. Hodder & Stoughton. (many printings, probably new editions). 

I find the best detailed exposition of Panini’s Ashtadhyayi to be the 6-volume work of Rama Nath Sharma, The Ashtadhyayi of Panini (without the diacritical marks, which unusually are incorporated in the printed title, no doubt a cataloguer’s nightmare!), published in 1987 (first edition) and revised and enlarged (second edition) in 2002, by Munshiram Manoharlal Publishers, New Delhi. Of course, being a detailed exposition in five volumes, it is for a serious pursuer of the subject! Volume 1 is a long (200-page) essay, covering such historical and biographical information as exists, then the various texts, commentaries and elucidations, both traditional and modern, theoretical considerations, various technical topics, and so on. Copious indexes, bibliographies, glossaries, etc. accompany the text. The sutras are given in both the Sanskrit type (Devanagari) as well as English transliteration.

Another well-known (and the earliest) modern  translation is Srisa Chandra Vasu’s Ashtadhyayi of Panini in 2 volumes (again, given here without the diacrictical marks that are very much there on the title page of the book!), originally published in 1891, and reprinted and published by Motilal Banarsidass Publishers, Delhi from 1962 (the copy I have seen is the 2009 reprint). According to Rama Nath Sharma, Vasu was the “only  English translation” of the Ashtadhyayi before his own work. He finds Vasu generally “trustworthy”, but is concerned that Vasu “takes a great deal for granted”, “omits glosses”, “misses explanatory details of terms and principles”, has a “pedantic style” of “archaic English”, and so on. My own feeling is that Vasu may be good for a first reading, whereas Sharma really goes into the details and has very subtle chains of reasoning, and may probably address the natural doubts of the learner better. Vasu is let down, I feel, by the fuzziness of its Devanagari typeface, which (at least for my bleary old eyes!) calls for the magnifying glass most of the time! It is available in archive.org for download:
https://archive.org/details/ashtadhyayi
https://archive.org/details/ashtadhyayitrans06paniuoft

I also happen to own an interesting Hindi translation Ashtadhyayi-Bhashya-Prathamavrtti in three volumes by Pandit Brahmdatta Jijnasu published by Ramlal Kapur Trust, Sonipath  (Haryana), which Rama Nath Sharma also refers to (not disapprovingly!). The interesting thing about having translations in different languages is that they sometimes tell us the different ways  in which the same technical terms or ideas can be interpreted and made less mysterious to us. I haven’t yet (December 2014) studied Jijnasu, but I did look up his translation of the term pragrhyam in sutra 1.1.11 (see Post 07); he also translates it as  - pragrhyam, which does not throw light on the common meaning of the term!

The vŗtti are mainly those provided in a work called the Kāśikāvŗtti, attributed to the duo Vāmana-Jayāditya of the city of Kāśi (Banares) in the 7^th century AD. The vāŗttika are in main attributed to the great Kātyāyana of the 3^rd century BC, and Rama Nath Sharma estimates (Sharma, Vol.I, p.6) that some 1250 of them (or around one-third of the sutras of the Ashtādhyāyi) have been quoted by the (even greater) sage and grammarian Patañjali in his Mahābhāshya or Great Commentary (2^nd century BC), the authoritative work on the Ashtādhyāyi and much else besides in philiosophy, logic etc. Indeed these three, Panini, Katyayana and Patanjali, are the “three sages” or “muni-trayah” of the linguistic heritage of Sanskrit.  Sharma categorically states that “Pāņini cannot be understood without the help of the commentaries, most notable among which is the Mahābhāşya” (Sharma, Vol.I, p.xi). There is a series of lectures on the Mahabhashya by Subrahmanya Sastri of the Annamalai University, volumes 1 to 6 of which are available for download at www.archives.org:

https://archive.org/details/LecturesOnPatanjalisVyakaranaMahabhashya1
https://archive.org/details/LecturesOnPatanjalisVyakaranaMahabhashya2
https://archive.org/details/LecturesOnPatanjalisVyakaranaMahabhashya3

https://archive.org/details/LecturesOnPatanjalisVyakaranaMahabhashya4
https://archive.org/details/LecturesOnPatanjalisVyakaranaMahabhashya5
https://archive.org/details/LecturesOnPatanjalisVyakaranaMahabhashya6

The later volumes (there are 8 more) up to Volume XI have been republished by the Kuppuswami Sastri Research Institute, 84, Thiru Vi. Ka. Road, Mylapore, Chennai-600004, www.ksrisanskrit.in (Phone +9144 2498 5320), well worth the trouble of getting these rare books. One hopes they will put them out on the web!

There is another variant of the Ashtadhyayi and commentary, the Siddhanta-Kaumudi of Bhattoji Dikshita, whose "eye for meticulous detail and interpretation" makes the work "the standard text for studying Panini" according to Sharma (Vol.I, p.26).

archive.org has other interesting works for download, e.g.
https://archive.org/details/Siddhanta_Kaumudi_English_Translation-SC_Vasu
https://archive.org/details/TheAshtadhyayiOfPanini-RamNathSharma

Vasu’s Ashtadhyayi can be downloaded here (comes in 8 files):

https://archive.org/details/ashtadhyayi