 In order to explore the problem space, we thus specifically target five binary classification problems addressed in BIBREF17 , BIBREF18 , i.e presence/absence of consonants, phonemic nasal, bilabial, high-front vowels and high-back vowels. 
 Question: What are the five different binary classification tasks?
 presence/absence of consonants, phonemic nasal, bilabial, high-front vowels and high-back vowels.