Metathesis was examined as a more or less systematic process that tends to preserve segments or features that would otherwise be lost or changed through the effects of other processes, notably reduction, assimilation, epenthesis, et al. It was also shown that metathesis is recessive as opposed to most other competing processes. With one exception, a direct correlation between susceptibility to metathesis and resonancy of the segment type was established. Formal types and some of the major causes of metathesis were investigated: reduction, open syllable canon, analogy, phonological constraints, anticipation, et al. (Author)