Segmentals weigh much more in comprehensibility than nuclear stress in read speech.

This study investigates the impact of segmental accuracy and nucleus placement on the comprehensibility of English as an International Language (EIL), with the aim of informing phonological norms and teaching models. Speech samples from 59 EIL speakers with varying levels of segmental accuracy were collected during a reading task, involving reading a passage in three different versions of speech, each version lasting approximately 30 to 40 s. To directly compare the impact of nuclear stress placement on comprehensibility, based on these samples, two versions of stimuli were created, each differing only in their placement of nuclear stress - either correct or incorrect. The correctness of placements was determined by seven native speakers of English. Eight native English speakers, aged 19-24, and eight EIL speakers, aged 20-24 with an upper-intermediate to advanced proficiency level, rated the comprehensibility of the two versions of speech. Results suggest that while correct nucleus placement enhances comprehensibility for native English listeners, it has little influence on EIL listeners. Segmental accuracy in EIL speech impacts comprehensibility substantially more than nucleus placement on both native and EIL listeners, indicating that English language teaching should focus on minimizing segmental errors to improve comprehensibility for EIL speakers, despite the benefits of correct nucleus placement.