spirants also called "fricatives." These sounds are created when the passage of air through the larynx and then out through the lips is impeded or restricted but not the passage is not completely closed: f, v, s, z, sh, ch, zh, kh.

sonants are voiced speech sounds, and can also describe syllabic consonants: u, w, l, r, m, n. Bely includes the semi-vowels u and w in this group.

Modern linguistics normally distinguishes between "obstruents" (stops, affricates and fricatives) and "sonorants" (nasals, liquids and semi-vowels). Meillet himself categorizes the sounds as "occlusives," "sifflantes," voyelles," and "sonantes." Cf. 53 ff.  

r'-l'-n'. The Russian language has palatalized consonants, the so-called soft consonants, traditionally indicated in phonetic transcriptions by a consonant letter followed by an '. The sounds are formed by raising the tongue rise in the mouth toward the palate.