Avestan language
"Zand" glosses and commentaries exist in several languages, including in the Avestan language itself. These Avestan language exegeses sometimes accompany the original text being commented upon, but are more often elsewhere in the canon. An example of exegesis in the Avestan language itself includes "Yasna" 19-21, which is a set of three Younger Avestan commentaries on the three Gathic Avestan 'high prayers' of "Yasna" 27. "Zand" also appear to have once existed in a variety of Middle Iranian languages, but of these Middle Iranian commentaries, the Middle Persian "zand" is the only to survive fully, and is for this reason regarded as 'the' "zand".