Usage-based phonology and simulations as means to investigate unintuitive voicing behavior

According to studies conducted by Coetzee & Pretorius (2010) and Rothenberg (1968), languages from the Sotho-Tswana group of Bantu languages demonstrate unintuitive voicing behavior in devoicing of post-nasal voiced plosives (/mb/-->[mp]) -- unintuitive in that greater articulatory effort is required to terminate voicing than to maintain it (Westbury & Keating, 1986). Nasals preceding stop consonants are said to have appeared in Bantu languages in order to facilitate production of voicing during the stop segment and were lost later during language evolutionary changes in languages like Swahili, Sotho or Duala (Meinhof, 1932). Current studies on Tswana and Shekgalagari (Coetzee & Pretorius, 2 010; Hyman, 2001; Solé et al., 2010), however, demonstrate that nasal segments remained in those languages – surprisingly not only before voiced stops but also before voiceless ones.We present an attempt at using computational simulations on voicing behavior of Tswana post-nasal stops. Previous approaches to phonological simulations (e.g. Boersma & Hamann, 2008) put a strong emphasis on the functional bias and its role in language change. We base our investigations on the assumption that the role of social biases might play even a higher role in the formation and change of phonologically and phonetically driven sociolinguistic processes (Nettle, 1999; Coetzee & Pretorius, 2010)