Speech Intelligibility
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Summary of Speech Intelligibility Testing Methods

 

Diagnostic Rhyme Test (DRT)

The DRT is one of the ANSI standards for measuring the intelligibility of speech over communication systems (ANSI S3.2-1989). The test materials consist of 96 rhyming monosyllable word pairs (i.e. veal-feel) that were selected to differ in only their initial consonant. These differences are categorized into six distinctive features and scores in each of these categories provide information on diagnosing system deficiencies. These six scores are averaged together to provide an overall measure of system intelligibility. The listener's task is to respond to the stimulus by indicating which of the two rhyming words presented before him was spoken.

 

Diagnostic Medial Consonant Test (DMCT)

The DMCT is a derivative of the DRT. Its test materials consist of 96 bi-syllable word pairs (i.e. stopper-stocker) that were selected to differ in only their intervocalic consonant. As with the DRT, these differences are categorized into six distinctive features and scores in each of these categories provide information on diagnosing system deficiencies. These six scores are averaged together to provide an overall measure of system intelligibility. The listener's task is to respond to the stimulus by indicating which of the two words presented before him was spoken.

 

Diagnostic Alliteration Test (DALT)

The DALT is also a derivative of the DRT. Its test materials consist of 96 monosyllable word pairs (i.e. pack-pat) that were selected to differ in only their final consonant. These differences are categorized into six distinctive features and scores in each of these categories provide information on diagnosing system deficiencies. These six scores are averaged together to provide an overall measure of system intelligibility. The listener's task is to respond to the stimulus by indicating which of the two words presented before him was spoken.

 

Modified Rhyme Test (MRT)

The MRT is one of the ANSI standards for measuring the intelligibility of speech over communication systems. The test materials consist of six 50 rhyming monosyllable word sets (i.e. pin,sin,tin,fin,din,win) that were selected with half to differ in the initial consonant and the other half in the final consonant. The listener's task is to respond to the stimulus by indicating which of the six rhyming words presented before him was spoken.

 

Phonetically Balanced Word List (PB)

The PB test is also one of the ANSI standards for measuring the intelligibility of speech over communication systems. The test materials consist of twenty 50 word list that are phonetically balanced. The listener's task is to respond to the stimulus by writing the word.

 

Spelling Alphabet Test (SpAT)

The SpAT is a test developed at the Navy for assessing word intelligibility using the ICAO words as the stimuli. The listeners task is to respond to the stimulus by writing the word or digit or by pressing the first letter of the word or the number on a keyboard.