Original: Freud theorized that children who experience conflicts during this period of time may develop "anal" personality traits, namely those associated with a child's efforts at excretory control: orderliness, stubbornness, a compulsion for control, as well as a generalized interest in collecting, possessing, and retaining objects.
Simplified: Freud made a theory which said that children who experience troubles during this time may develop "anal" personality traits, as well as a general interest in collecting and keeping things.