Phonaestheme is a morpheme whose speech sound denotes some similar sense as its word form. It not only has function of word generation, involved in the cognition and formation of new words, but also represents specific cultural norms indirectly and metaphorically. This paper takes phonaestheme sn- as an example to elaborate the externalization, internalization and metaphorization of English phonaestheme symbols, and to demonstrate its cultural and cognitive attributes of 'derogation'.