early plural comprehension?

[Michael Tomasello]

Brian,

The youngest children to add English plural -s in a production 
experiment with novel verbs are, to my knowledge, 21-22 months (4 of 10 
children at least once).  I know of no preferential looking experiments 
examining this with novel verbs.  Reference:

Tomasello, M., Akhtar, N., & Dodson, K., Rekau, L. (1997). Differential 
productivity in young children's use of nouns and verbs.  Journal of 
Child Language, 24, 373-87.

Best,

Mike