The command line way to control Airport is
networksetup | grep airport in the Terminal reveals:
Usage: networksetup -getairportnetwork <device name>
Usage: networksetup -setairportnetwork <network> <device name> [password]
Usage: networksetup -getairportpower <device name>
Usage: networksetup -setairportpower <device name> <on off>
So this is what you want for controlling AirPort.
Mac OS X v10.4 added Automator workflows which can also be used as Speakable items.
If a workflow is saved as an application and put in the Speakable items folder it becomes available to the speech recognition software. The words the computer will recognize to execute the command will be the name of the saved Automator application. Some words might have to be misspelt for the computer to know the proper pronunciation. (For example, the computer best recognizes "Les Misérables" as Lay Mizzer Ob).
You can determine the location of speakable items by going to System Preferences, Speech, Speech Recognition, Open Seakable Items Folder. For me, it's
Create an Automator application using the Run Shell Script item, call
networksetup with appropriate parameters (e.g.
networksetup -setairportpower en1 on for enabling), save it as an application, store it in the speakable items directory determined above. Use the command you want to speak as application name.
Edited to add:
Here was another answer previously regarding the log. I think it refered to
AirPort (or type
AirPort in the Console.app search box after selecting
/private/var/log in the tree on the left) and you should see corresponding log messages, including
AirPort: Link Down on en1. Reason 8 (Disassociated because station leaving).
AirPort: Link Up on en1