Refraction occurs when light passing from one medium to another

Two-word semantic relations

By 2 years most children are beginning to combine words into simple 2 word phrases

Item-based constructions

Children are learning to make sentences not by learning the abstract syntactic function of words but by hearing how words are involved and what functions were being performed.

representational gestures

Signify some features of an object or its function such as pretending to eat with a spoon, or they can be social in nature such as waving good bye.

Holophrase

a single word used by a young child that conveys meaning that is more like a sentence: where is daddy? daddy come here. daddy is home.

deictic gestures

call attention to or indicate an object or event ex: it is right here pointing gestures

Pivot-open grammar

particular words or phrases with predictable pragmatic functions that are used repeatedly to structure utterances Ex more milk more juice more candy

protoimperative pointing

protoimperative pointing-]gestures used by children to control or manipulate the behaviors of others. Pointing to milk for his milk bottle or shaking head to say he's done.

protodeclarative pointing

to describe when a child points to the objects or events of focus by the child and adult.Ex; pointing to cow to establish is fastinating creature "hey look at that"