How are Quechuan and Aymaran languages related in the Quechumaran stock?

The Quechumaran stock is a linguistic grouping composed of the Quechuan and Aymaran language families.12

While some scholars classify these two groups together within the Quechumaran stock, the relationship is not universally accepted as a proven genetic connection. In the study of South American Indian languages, determining such relationships is complex; classifications often rely on vocabulary comparisons and structural similarities rather than the rigorous application of the comparative method. Consequently, no convincing evidence for a further genetic relationship between the two families has been established, and the classification remains a subject of scholarly discussion rather than a confirmed linguistic fact.1234