When Do Children Learn the Comparative?

[Peyton Todd]

Does anyone know when children normally learn the -er (comparative) suffix in English, also the 'more + Adjective' alternate? What about children learning other languages? Supposedly, if they can't seriate until concrete operations, they would presumably not understand the comparative, but of course they might still utter it, and just use it to choose between pairs of objects. What actually happens?

Thanks!

Peyton Todd