Students in Germany have successfully petitioned for their marks in an English-language examination to be changed partly because it contained a poor recording of Prince Harry "mumbling" in a speech, BBC reported.

Officials in the North Rhine-Westphalia, Germany's most populous state, agreed to change the test after an online petition collected more than 43,000 students' signatures.

Students also complained about a question on apartheid in South Africa, for its difficult vocabulary.

The examination was part of the state's middle-school leaving exams and counted for half of all the marks in English.

The results the 16-year-old students got would determine what apprenticeships they can do after secondary school.

Student Dario Schramm, 16, launched the online petition last Thursday (May 18), and it quickly drew thousands of signatures, German media reported.

There was "loud background noise" in Prince Harry's speech, he said. It was a speech on Aids that the prince gave at a children's centre in Lesotho in 2015.

"Some students were extremely upset, there was weeping and great disappointment," a headmaster in Düsseldorf, Bernd Hinke, was quoted as saying.

In response to the complaints, the English exam marks are being revised, BBC said.