Background: The Digits-in-Noise (DIN) test is an adaptive speech-in-noise assessment that measures speech reception thresholds (SRTs) using digit triplets. While DIN tests are available in multiple languages, studies investigating the effect of second-language proficiency and its combined effect with hearing loss on DIN test outcomes are limited. This study investigates the effect of second-language proficiency on DIN outcomes by comparing Turkish and Dutch DIN tests in native Turkish speakers with varying Dutch language proficiency and different hearing levels.

Methods: In this ongoing study, so far nine native Turkish individuals between the ages of 18-65 yr were included. Participants’ Dutch proficiency levels range from A0 to C1 according to the Common European Framework of Reference for Languages (CEFR). Participants underwent pure tone audiometry (0.25-8 kHz), performed the Turkish Child-friendly Coordinate Response Measure (T-CCRM) test, and DIN tests in both Turkish and Dutch. The DIN test implementations had two variables: (1) Sound presentation, which could be diotic or antiphasic; and (2) Speaker, including Dutch male, Turkish male, or Turkish female. For all six tests, noise level was fixed at 65 dB SPL and the starting SNR was -6 dB.

Results and Discussion: Preliminary data of participants with varying levels of hearing acuity indicate observable trends (with no statistical analyses yet). Turkish DIN SRTs, for both male and female speakers, seem slightly lower than Dutch DIN SRTs. Dutch language proficiency seems to positively affect the Dutch DIN test outcomes. Increased hearing loss seems to negatively affect DIN SRTs in both languages, aligning with expectations. Antiphasic sound presentation resulted in lower DIN SRTs compared to diotic. T-CCRM scores were generally within normal ranges but showed decreased performance at an SNR of –6 dB, possibly due to the influence of participants with hearing loss. Data collection is ongoing, and these findings will be expanded and re-evaluated with additional participants by the 16th Speech in Noise (SpiN) Workshop.