Is "house" a valid command? VoiceAttack is intended to recognize specific commands (when not set up explicitly in its dictation mode), so anything that cannot be recognized as a command is therefore "unrecognized" (meaning, what was recognized could not be matched to a known command, I.E. VoiceAttack has not been given instructions on how to respond to that input)
If you only want the log to show recognized commands, right-click it and click "Do not show unrecognized items"