A third of applicants for Birmingham taxi and private hire licences failed a basic communications test.
The 20-minute written exam was introduced by the city council following complaints from passengers about language barriers.
More than 500 drivers were refused licences last year after failing at least one of the sections of the test.
A statistical breakdown issued by the council showed 40 per cent of Pakistani, 43 per cent of Indian and 49 per cent of Bangladeshi applicants did not pass the test.
More than 1,100 drivers passed the test.
Under a section headed best answers, applicants were read a sentence and asked to choose a suitable reply.
1) Your passenger asks if you allow guide dogs in your car? You reply: a) In the boot. b) Next month. c) Thank you. d) Yes, of course.
2) Your passenger asks you if you would help carry their luggage. You reply: a) In the morning. b) On Friday. c) Sometimes. d) Yes, of course.
Numerical questions asked applicants to work out typical cab fares, to calculate change and deduct tips.
Testing for prospective taxi and private hire drivers began in April 2002 after the council said it had evidence that Asian drivers experienced a disproportionately high number of physical attacks because passengers were frustrated by communication problems.
Jacqui Kennedy, council assistant director for regulatory services, said: " Consultation was carried out with drivers before the scheme was piloted with all drivers feeling that the test was relevant to the job that they would be undertaking.
"There were no objections to the test being introduced."