At the word level we look for particular patterns of errors that may provide information about underlying phonological processes. Extensive errors may reflect a poorly developed phonological system. They may also reflect underlying physiological deviations such as inappropriate modulation of voice onset or insufficient control of air expenditure.
The FSST4 is a test that is particularly valuable for assessment when such underlying deviations occur at this level.
We have found that describing errors to students using a distinctive feature approach with traditional notions of place, manner, and voicing is valuable, particularly as an instructional tool. For example, distinctive feature terminology is valuable when describing visual information on a speech spectrogram.
Older students tend to appreciate this descriptive information as it enhances their metacognitive understanding of speech production. Primarily for this reason, we have continued to use the Fisher-Logemann Test of Articulation Competence3 which has a scoring sheet that partitions errors into place, manner, and voicing categories. Identifying errors and discerning patterns and processes is a critical step in the assessment process.
Some speech samples are presented here to illustrate a variety of phonetic errors and the acoustic effects of poorly coordinated respiration, phonation, and articulation:
|These words show difficulty managing voicing. Notice that phonemes are voiced in initial and medial position of words but devoiced in final position; notice also the extraneous voicing following glottal plosives.|
|These words show difficulty controlling air for fricative and plosive manner of production; notice also the difficulty controlling the onset/offset of voicing.|
|These words show nasal substitutions for initial sounds with different manners of production; notice correct production for /m/ and /n/.|
|These words show a substitution of a plosive manner of production for nasals and glides.|
|Notice how control of air expenditure and glottal and velar variations influence the production of these words.|
|Notice how vocal tension interferes with the coarticulatory aspects of speech production.|
|Notice the elevated pitch and resonance changes that occur with certain words; follow-up assessment should determine whether such changes are systematic or random.|
|Notice how first language phonology influences production.|