Usability Testing is nothing but the application is user 
friendly or not. i.e easy to use and easy to operate.

UT :
Testing the ease with which users can learn and use a 
product.

There no automation tools available for usability testing

usability testing is not related to tester.
this is done by collecting the suggestions of end users

Usability Testing is nothing but testing an intended user 
of the system can carry out the intended task efficiently.

usually this testing is done before going to production
by then all the  bugs found  are fixed and closed.

the test scenarios are used to verify the usability.
mainly the participants are atleast:
1 user representetive
1 test host
1 dveloper
1 business representetive.

usually observers are in separate rooms or on separate 
machines,and no.of sessions they do is depend on the 
complexity of the application.

usually in about 10 session most of the uncovered issues 
can be found.

Testing for 'user-friendliness'. Clearly this is 
subjective, and will depend on the targeted end-user or 
customer.

UT means to test 'how simple the application to use'.

usability testing is nothing but testing the applivation 
whether it is user friendly or not
in usability testing,we will check font size,font 
color,back color,tables,borders etc.. but the above 
requirements by the customer is rare

mm

Please maintain some basic ethics