Mr. Kyori Suzuki (Master's student) of the CLR Phonetics Lab has developed a free iOS app "VisualLearning" for studying English pronunciation and English phonetics. It is now available in Apple's "App Store" for iPhones from October 31.
With this app, you can learn English pronunciation visually and audibly by viewing ultrasound video of the native speaker's tongue movement, and by comparing it with the video of your own pronunciation.
In August, Mr. Suzuki made a presentation of this app at an international conference "Interspeech 2017" (※1) in Stockholm, Sweden.