the distinction is not rigorous. for example, when voiced obstruent geminates appear with another voiced obstruent they can undergo optional devoicing (e.g. "doreddo" ~ "doretto" 'dreadlocks'). attributes this to a less reliable distinction between voiced and voiceless geminates compared to the same distinction in non-geminated consonants, noting that speakers may have difficulty distinguishing them due to the partial devoicing of voiced geminates and their resistance to the weakening process mentioned above, both of which can make them sound like voiceless geminates.