In this study, we will evaluate how solo, naive listeners perceive the speech of people with amyotrophic lateral sclerosis (ALS) and age-matched speakers produced across interactive and non-interactive contexts with an unfamiliar, naive interlocutor.

Listeners will hear recorded speech of PALS and age-matched speakers and indicate what they heard. Recorded speech consists of vowels and consonants produced in non-interactive and interactive tasks. The perceptual judgements will be compared to see whether interactive contexts have similar perceptual effects across the two groups.

Plans for Assignment - This is a single group study in which all participants will engage in the same tasks.

Delivery of Intervention: Solo listeners will participate in this study in a remote, asynchronous format. They will be recruited using the online participant recruitment platform Prolific © and will use their own laptop/computer and headphones.

Adequacy of Sample size: We will use n = 1300 listeners to achieve 80% power at alpha of .05 to detect between group differences with the assumption of medium effect sizes (Cohen's f = 0.3).

Adequacy of Analyses: The proposed statistical analyses (Generalized mixed effects regressions) are standard and will be used to analyze the effect of the intervention on the outcome measures described below.

Inclusion Criteria:

• passing the remote hearing screening
• having no known speech, language or neurological disorders per self-report
• being a native monolingual speaker of American English
• having no experience communicating with people with dysarthria
• being between the ages of 18 and 65.

Exclusion Criteria:

• None - if volunteer meets the inclusion criteria, then they will be enrolled

The project will involve the collection of perceptual judgments and questionnaire data. All deidentified data will be shared through the Open Science Framework (osf.io). All scripts, protocols, procedures, and analyses will be shared along with the deidentified data to ensure that other researchers can verify and build on the presented results. All shared data will be made available in a format that is accessible by open-access software (e.g., R, Open Office, pdf reader). In addition, platform-specific scripts (e.g., experimental software LabVanced) will be shared with explanations so that they may be implemented across different software environments.

Data will be shared after publication of the study.

All deidentified data, metadata, and related tools will be freely available via Open Science Framework (OSF). The original audio files will be made available (for participants who consent) by request from researchers in the field to ensure responsible use.