People with clinically defined normal hearing frequently report difficulty hearing in challenging environments. They often leave audiology clinics with no diagnosis to explain the difficulty they experience listening in noise. Studies in adults demonstrate that extended high frequency (EHF; > 8 kHz) hearing, beyond the currently tested range of clinical audiometry, contributes to speech perception in noise. Young children are the most sensitive to EHFs, and this sensitivity is progressively lost throughout the remainder of life. Previous studies found a significant relationship between EHF hearing loss (EHFHL) and difficulty understanding speech-in-noise (SiN) in adults with clinically normal hearing. However, to our knowledge, no studies have investigated this relationship in typically-developing, normal-hearing children and youth. The present study aims to address this gap by investigating the association between EHFHL and impaired SiN perception in children and young adults (8 to 30 y/o) with clinically normal hearing (≤ 20 dB HL, 0.25 - 0.8 kHz). There are three specific aims. In Aim 1 we will establish the relationship between EHFHL and subjective reports of listening difficulties using standard (0.25-8 kHz) and EHF (9 - 16 kHz) audiometry. The adult and child versions of the Speech, Spatial and Qualities (SSQ) questionnaire will measure self- and parent-reported difficulty listening in noise. In Aim 2 we will determine the impact of EHFHL on the perception of spatial speech using the sound-field digits-in-noise (sfDIN) test. In Aim 3, we will evaluate low-frequency correlates of EHFHL and their possible effect on SiN. Objective (chirp transient- evoked otoacoustic emissions) and behavioral (spectro-temporal modulation task) measures of supra-threshold hearing will be used to determine whether supra-threshold deficits at standard frequencies (≤ 8 kHz) account for associations between EHFHL and SiN that have been observed for adults and are predicted for children. Outcomes of these experiments will enhance our understanding of the impact of EHFHL on communication abilities of children. If EHFHL contributes to the difficulty children experience in challenging environments, as we hypothesize, then including EHF hearing assessment in an audiologic test battery could identify susceptible individuals and in turn lead to prevention and early intervention for hearing loss.