Modified rhyme test

A quite different approach focuses on word recognition and tests of this type are perhaps the most common sort of intelligibility test. Here listeners are played words either in isolation or in sentences and asked which word(s) they have heard. One group of tests plays listeners similar words and asks them to make distinctions. The most commonly used test is perhaps the modified rhyme test (MRT) [221]. In this test, listeners are played a set of 50 groups 6 words each. The words in each group are similar and differ in only one consonant and the users are asked to record which word they have heard on a multiple choice sheet. A typical set of words might be BAD BAC K... 

Intelligibility testing is often performed with the modified rhyme test or semantically unpredictable sentences. While these give a measure of word recognition, care should be taken when using results from these tests to indicate performance in applications, naturalness is normally measured by mean opinion scores (MOS). 

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