Suitability of self-recordings and video calls: Vowel formants and nasal spectra

Abstract

When the COVID-19 pandemic halted in-person data collection, many linguists adopted new online technologies to replace traditional methods. These included VoIP video conferencing apps like Zoom, which allow live interaction with participants, as well as user-led options in which participants record themselves using personal computers or smartphones and then email or otherwise transfer the sound files to researchers online. This study evaluated the suitability of such recordings for phonetic analysis of vowel space configurations, mergers, and nasalization by comparing simultaneous recordings from several popular personal devices (Macbook, PC laptop, iPad, iPhone, Android phone) and video call apps (Zoom, Skype, Teams) to those taken from professional equipment (H4n field recorder, Focusrite with table-top microphone). All personal devices and apps conveyed vowel arrangements and nasalization patterns relatively faithfully (especially laptops), but absolute measurements varied, particularly for the female speaker and in the 750-1500 Hz range, which affected the locations (F1xF2) of low and back vowels and reduced nasalization measurements (A1-P0) for the female's pre-nasal vowels. Based on these results we assess the validity of remote recording using these devices and offer recommendations for best practices for collecting high fidelity acoustic phonetic data from a distance.