The validity of PEA as a genetic subgroup has been disputed by Pentland and Proulx. Pentland questions the Eastern Algonquian status of the southern New England languages and Powhatan and Carolina Algonquian. Proulx has proposed that the similarities can be explained as the result of diffusion. Goddard has countered that the extent of the similarities would require extensive diffusion very early in the breakup of the Eastern Algonquian languages and that such a position would be difficult in principle to differentiate from analyzing PEA as a genetic subgroup.