“…While a number of speech decoding studies have been conducted using EEG recently such as for classification of imagined syllables (D'Zmura et al, 2009;Brigham and Vijaya Kumar, 2010;Deng et al, 2010), isolated phonemes (Chi and John, 2011;Leuthardt et al, 2011;Zhao and Rudzicz, 2015;Yoshimura et al, 2016), alphabets (Wang et al, 2018), or words (Porbadnigk et al, 2009;Nguyen et al, 2017;Rezazadeh Sereshkeh et al, 2017), the decoding performances have been intermediate, e.g., 63.45% for a binary (yes/no) classification (Rezazadeh Sereshkeh et al, 2017) or 35.68% for five vowel classification (Cooney et al, 2019a). There are inherent disadvantages in using EEG that may have contributed to the difficulty in attaining high decoding performance.…”