There has been great difficulty in forming clear subfamilies within Indo-Aryan. Some of the issues are whether Gujarati is more affiliated with Marathi–Konkani or with Hindi (and Rajasthani); whether Dardic constitutes an areal zone, an Indo-Aryan genetic group, or a separate Indo-Iranian subfamily; whether Eastern Hindi is allied with Western Hindi or Bihari; and whether a Northwestern zone encompasses Punjabi or not. Ultimately, in an area with high linguistic contact such as South Asia, the deficiencies of the tree model are apparent.