[9] The earliest work on pronunciation assessment avoided measuring genuine listener intelligibility,[10] a shortcoming corrected in 2011 at the Toyohashi University of Technology,[11] and included in the Versant high-stakes English fluency assessment from Pearson[12] and mobile apps from 17zuoye Education & Technology,[13] but still missing in 2023 products from Google Search,[14] Microsoft,[15] Educational Testing Service,[16] Speechace,[17] and ELSA.
[23] In the Common European Framework of Reference for Languages (CEFR) assessment criteria for "overall phonological control", intelligibility outweighs formally correct pronunciation at all levels.
[27][28] Such evaluation databases often emphasize formally unaccented pronunciation to the exclusion of genuine intelligibility evident from blinded listener transcriptions.
[29] Some promising areas for improvement being developed in 2024 include articulatory feature extraction[30][31][32] and transfer learning to suppress unnecessary corrections.
[33] Other interesting advances under development include "augmented reality" interfaces for mobile devices using optical character recognition to provide pronunciation training on text found in user environments.