“…Studies on direct classification (Ali et al, 1999; Anjos et al, 2020; Clarkson & Moreno, 1999; Esposito & Ceglia, 1999; Fredj & Kaïs, 2014; Graves et al, 2005; Lee & Hon, 1989; Malakar, 2021; Meenakshi & Ghosh, 2017; Mukherjee et al, 2018; Myrvoll, 1999; Waibel et al, 1988; Waterhouse & Cook, 1997; Zahorian et al, 1997) indicate the inherent difficulties involved in the approach. For example, the comparison with all phoneme classes is performed at the same time, which in turn increases the processing time (Koizumi et al, 1996).…”