Abnormal 21 month old child behavior

[Cindy12601]

Yesterday, I noticed my 21 month old son was not communicating and was avoiding engaging in activities where his normal reaction would be to laugh or exhibit a reaction where his mouth would need to open. I later discovered he was holding food in mouth for a couple of hours.
  I am a bit concerned by this new behavior and I'm wondering if it truly is cause for concern.
  Is his behavior normal?

[margypops]

yes I would say hes playing games and if he saw you making much of it, it became a good game to get attention ..how do you know food was in his mouth fir a couple of hours ?