Updated Overview (markdown)

Overview.md

@@ -2,10 +2,9 @@ The Bot Builder SDK v4 is a modular and extensible framework for developing bots
 A bot is an application than can communicate conversationally with a user. A bot may be as simple as a basic pattern matching algorithm that returns a response, or it may include artificial intelligence, complex conversational state, and integration with existing business services.
 
 ## Architecture
-The SDK defines a _bot framework adapter_ object that can communicate with a user over various channels.
-this adapter also defines a _middleware_ collection.
+The SDK defines a _bot adapter_ object that can communicate with a user over various channels, and defines a _middleware_ collection that allows you to add reusable components to your application.
 
-## The bot framework adapter
+## The bot adapter
 Your application should pass an incoming request as an activity, with associated authentication information, to the adapter.
 The adapter handles authentication, processes the activity, and sends any outbound activities through a connector back to the channel.