1.       Consonant errors generally cause more problems with comprehensibility than vowel errors or syllabic structure errors, but with some caveats.

◊ Coda [k] deletion in “ask her” was considered to be more accented than coda [v] deletion in “five thick.” The most accented sounds were those with a nonnative sound, such as the retroflex [ɭ] and the trill [r]; however, the native consonant phonemes, such as [θ]> [f] were rated as relatively less accented. (Gao Z., & Weinberger, S., 2018.)  

To hear these particular sounds, visit this interactive IPA chart below.

2.       For the most part, vowel pronunciation errors did not affect comprehensibility as much as consonant errors, with the following exceptions:

◊ Sounds with cluster internal (vowel) epenthesis (i.e. [pʰl] to [pʰəl]) and those with coda epenthesis (i.e. [aesk] > [aeskə] sounded more accented than sounds with consonant errors. (Gao Z., & Weinberger, S., 2018.)

3.    Comprehensibility was related to all linguistic domains: segmental, prosodic, temporal, lexical, and grammatical analysis. However, the most “accented” speech was mostly associated with segmental sounds. (Saito, K., & Trofimovich, P., & Isaacs, T., 2016.)

 

The connections of this research to what I’ve learned in class center on realizing the importance of developing a basic understanding of IPA symbols, which I can connect with my students' speech, and help correct it if comprehensibility is negatively impacted. 

Also, because all of my students share the same L1, I'm able to see patterns with common pronunciation errors affecting comprehensibility that almost all of my students exhibit, such as vowel epenthesis and coda consonant deletion, especially with the velar and alveolar stops. 

Gao, Z., & Weinberger, S. (2018). Which phonetic features should pronunciation Instructions focus on? An evaluation on the accentedness of segmental/syllable errors in L2 speech, Research in Language, 16(2), 135-154. doi: https://doi.org/10.2478/rela-2018-0012

 

SAITO, K., TROFIMOVICH, P., & ISAACS, T. (2016). Second language speech production: Investigating linguistic correlates of comprehensibility and accentedness for learners at different ability levels. Applied Psycholinguistics, 37(2), 217-240. doi:10.1017/S0142716414000502.