Expanding Interaction Potentials within Virtual Environments: Investigating the Usability of Speech and Manual Input Modes for Decoupled Interaction

Table 1

Qualitative comments from IDU questionnaire.

	Advantages of speech	Disadvantages of speech
User trial 1	(i) Good for interacting with objects within the environment; (ii) More natural form of command than typing (or moving a mouse); (iii) Did not have to think as much when deciding how to interact with the environment; (iv) Made control of VE more relaxing and less intense; (v) It was quick once you knew the command; (vi) It was simple to use	(i) Not the most natural method for moving in a VE; (ii) Microphones can be too large, bulky and intrusive; (iii) Commands can take time to perfect; (iv) Joystick/keyboard easier for controlling movement; (v) Felt self-conscious; (vi) Not sure what commands to use
User trial 2	(i) Could handle several instructions in one command; (ii) Less strenuous than using a mouse/joystick; (iii) No real learning process required; (iv) Natural language—the ultimate user interface	(i) Too easy to say one thing when you mean another; (ii) Not good for trivial repetitive tasks; (iii) Have to add instructions when initial instructions are not carried out; (iv) Not sure what are acceptable commands; (v) Microphones can be too large, bulky and intrusive
Expert evaluation group	(i) Good for selecting menus; (ii) Good for simple instructions; (iii) Good for menus and settings; (iv) Natural provided it works!; (v) Good for multitasking; (vi) Adds to already available interactions when with existing input devices, especially in a “busy” VE; (vii) Single word can initiate a complex automated procedure; (viii) Hands free, allow other tasks to be performed	(i) Could be disturbed by other people; (ii) Might feel self-conscious; (iii) Fine adjustment manipulation may prove difficult; (iv) Might be difficult for navigation; (v) Interaction metaphors not as precise as using joystick or mouse; (vi) Inaccurate if user loses concentration; (vii) Dislike using for locomotion; (viii) Could lead to side effects