1-study matrial - linguistics -First Language Acquisition - Fourth stage
2-study matrial - linguistics - Discourse Analysis - Fourth stage
3-study matrial - linguistics - Gestures and sign Language - Fourth stage
4-study matrial - linguistics - Language and culture - Fourth stage
5-study matrial - linguistics - Language and regional variation- Fourth stage
6-study matrial - linguistics - Language and social variation - Fourth stage
7-study matrial - linguistics - Language history and Change - Fourth stage
8-study matrial - linguistics - Pragmatics- Fourth stage
9-study matrial - linguistics - Second language Acquisition- Fourth stage
10-study matrial - linguistics - The Origins of Language - Fourth stage
