RT Journal Article SR Electronic(1) A1 Callaghan, Catherine A. YR 1997 T1 Progress on the Origin of Language? JF Diachronica VO 14 IS 2 SP 345 OP 362 DO https://doi.org/10.1075/dia.14.2.07cal PB John Benjamins SN 0176-4225, AB , UL https://www.jbe-platform.com/content/journals/10.1075/dia.14.2.07cal