... has nearly nothing to do with the topic at hand.
AutoHotkey uses the plain old Win32 API; whatever is needed for a given command. For instance, Send uses keybd_event, SendInput or a journal playback hook depending on the mode. WinMove uses MoveWindow. A lot of the Gui code and Control commands use SendMessage. If you're a C/C++ programmer, you can easily use these APIs directly, but AutoHotkey simplifies many things.
AutoHotkey covers a wider range of functions than UI Accessibility and Active Accessibility (aka IAccessibility). However, unlike AutoHotkey's commands, UI Accessibility and AA are able to recognize UI elements which aren't implemented as windows (such as elements within a webpage), even if what you can do with those UI elements is rather limited.