I asume that you are removing it by right clicking the taskbar and unselecting it under tool bar? Or are you just right clicking on the language bar itself and clicking close language bar? Either way should work. If it is coming back after start up you could always right click the start button go to properties, then select the taskbar tab go to customize and select always hide under behavior. Another solution may be to click start run and type msconfig and make sure that the language bar is not listed under the start up tab.

Conrtrol Panel -> Regional & Language Options -> Languages Tab -> Details Button -> Language Bar Button -> uncheck all boxes