the discussion of how categorical features are determined is still up for debate and there have been numerous other theories trying to explain how words get their meanings and surface in a category. this is an issue within categorical distinction theories that has not yet come to a conclusion which is agreed upon in the linguistic community. this is interesting because phi-features in terms of person, number and gender are concrete features that have been observed numerous times in natural languages, and are consistent patterns that are rooted in rule-based grammar.