ones include initial stop-approximant (e.g. Thai ) and initial fricative-liquid (e.g. English ) sequences. More rare are sequences which defy the SSP such as Proto-Indo-European and (which many of its descendants have, including English).

Certain consonants are more or less likely to appear in consonant clusters, especially in certain positions. The Tsou language of Taiwan has initial clusters such as , which does not violate the sonority sequencing