How much 'custom' (society) determines the behaviour of an individual can be predicted by looking at that person's vocabulary. It is predicted that the more this person's 'baby talk' words are part of his own family's everyday vocabulary/speech, then this person is more able to affect traditional custom rather than be shaped by traditional custom. Conversely, the less his 'baby talk' words are adopted by his immediate family, then the less he can influence traditional custom, and the more traditional custom will shape his behaviour.