John Campbell states, after his own field work among the Sarakatsani in the 1950s, that the Sarakatsani are in a different position from the Vlachs, meaning the Aromanians and the Arvanitovlachs. The Vlachs are usually bilingual in Greek and Aromanian, while the Sarakatsani communities have always spoken only Greek and have known no other language. He also asserts that the increasing pressure on the limited areas available for winter grazing in the coastal plains has resulted in disputes between the two groups on the use of the pastures. In addition, during the time of his research, many Vlachs often lived in substantial villages where shepherding was not among their occupations, and demonstrated different art forms, values and institutions, from those of the Sarakatsani. The Sarakatsani also differ from the Vlachs in that they dower their daughters, assign a lower position to women and adhere to an even stricter patriarchal structure.