Reach is a type of Communicate. Sound can be used for Communicate. Pat is a type of Sound. Pat is a type of Teacher. 
Discourse is a synonym of Discuss. Discuss is related to Talk. Level is a type of Talk. Level is related to Certain. 
Reach --IsA--> Communicate <--UsedFor-- Sound <--IsA-- Pat --IsA--> Teacher 
Discourse <--Synonym--> Discuss <--RelatedTo--> Talk <--IsA-- Level <--RelatedTo--> Certain 