Halliday & Matthiessen (1999: 527):
These include comments about how desirable or plausible or self-evident something is, expressions of attitude in referring to persons and objects, sets of words with similar experiential meaning but distinguished interpersonally by connotation (sometimes called “purr words” and “snarl words”) and numerous forms of personal address and reference (kinship terms, personal names, honorifics, endearments, insults and the like).