Question : mac os 10.49  voice that talks whenever I use an application

i want to disable

if I use firefox
i hear
'firefox'

if i use itunes
i hear
'itunes'

if i turn down volume
'volume x percent'

Answer : mac os 10.49  voice that talks whenever I use an application

Or simply hit Command + F5.

Also check out in System Preferences the Keyboard shortcuts and disable: Turn Voice Over on or off. People often turn voice over by accidentally hitting Command + F5