Visible Vowels is a web app that makes it very easy to visualize acoustic vowel measurements such as f0, formants and duration. Those measurements may be made with programs like Praat, Speech Filing System (SFS) and WaveSurfer. Visible Vowels is a useful instrument for research in phonetics, sociolinguistics, dialectology, forensic linguistics, and speech-language pathology. The program has been developed at the Fryske Akademy (Leeuwarden, The Netherlands) by Wilbert Heeringa under supervision of Hans Van de Velde (Heeringa & Van de Velde 2018). In this lecture you are introduced to the the possibilities of Visible Vowels.