facial expressions (along with body posture) carry meaning and may be a more
ancient form of communication than language.  also, the infant is capable of
communicating via facial expression very soon after birth, and such affective
communication constitutes an important means of communication in infancy. 

http://www.economist.com/node/9111472

@article{bloom-capatides-87_affect-expression-delays-language-acquisition,
  title={Expression of affect and the emergence of language},
  author={Bloom, L. and Capatides, J.B.},
  journal={Child Development},
  pages={1513--1522},
  year={1987},
  annote = {

based on comparing % of time the infant expresses facial emotion, vs the age
of first word (FW) and vocabulary spurt (VS). 

the more frequently the children expressed emotion, the older the age of
language achievements. 
also, opposite: the more time spent in
neutral affect, the younger the age of language achievements. 

seems a negative result - the less emotion your child learns, the earlier her
language.  but then, emotion expression is also a function of parental
affective display - so shd parents not smile at their babies? 

}}

facial expression analysis
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