Was the Khotanese Brāhmī subscript hook borrowed from the Kharoṣṭhī anusvāra?

The sign inventory of the Brāhmī script used to write down Khotanese, an eastern MiddleIranian language once spoken in the southwest of the Tarim Basin, includes threeadditional diacritics. These are the two dots over an akṣara, the St. Andrew’s cross, andthe subscript hook. The first two diacritics have already been detected in severalKharoṣṭhī documents from the Khotan area. In Khotanese, they represent respectively әand aә. The subscript hook, on the other hand, seems to be restricted to KhotaneseBrāhmī, but its specific linguistic function, palaeographical developments, and ultimateorigin are still a matter of debate among scholars. This article offers a critical overviewof the relevant scientific literature and introduces the results of a preliminary palaeographicalanalysis of the diacritic. The analysis shows that the subscript hook used inKhotanese Brāhmī was borrowed from the Kharoṣṭhī anusvāra. The proposed borrowingtrajectory sheds light on the linguistic function of the diacritic as well.