a. Metathesis applies across a morpheme boundary, but not a word boundary.

b. Following segment: Metathesis applies before any consonant.
__ stop ---> mezge ---> meksk ---> meksti ---> knit; 3rd past, imper. sg., inf.
__ fricative ---> triʃko
trikʃta(< triʃk-sta; see Related processes) sprout; present, past
__ liquid ---> nyurzgya ---> nyurgzli:s ---> growl; 3rd pres., agent noun

c. Preceding segment:
i. Metathesis occurs when the fricative/stop sequence is preceded by a vowel. Also, although there are no alternations showing metathesis when a nasal consonant precedes, all surface sequences with a preceding nasal reveal the same order as would be expected had metathesis applied, i.e. Vŋ(k)[fric]C, not *Vn[fric]kC, e.g. bruŋ(g)zge, bruŋ(k)sk 'grinding stone; 3rd sg. past, imper.sg.'.
ii. Metathesis occurs when the fricative/stop sequence is preceded by a liquid, e.g. urzge, urksk, urksti ‘to grumble; 3rd sg. past, imper.sg., infin.’

d. Stress plays no role; metathesis applies regardless of whether the adjacent context is stressed or unstressed, e.g. mézge, méksk, méksti, megzlí:s ‘knit; 3rd past, imper. sg., infin., agent noun’. Compare Faroese metathesis in which stress is relevant.

e. As a synchronic phonological process, the direction of change in metathesis is: [fricative] [stop] -> [stop][fricative], when preceded by a sonorant and followed by a consonant, e.g. /plyesk-ti/ -> [plyeksti] 'to flash intensely', cf. [plyeske]. See Seo & Hume 2000 for evidence supporting this direction.

Nasal metathesis is applied when the stem ends in an obstruent. The nasal infix is realised as [n] if it is not followed by an obstruent.

/kup + ŋ + a/ klum̃pa 'he trips'
/plau + ŋ + a/ plauna 'he washes'


Stress does not play any role in metathesis. Regardless of stress, metathesis applies when contexts are met.

Perceptual optimization (Seo & Hume 2000; Steriade 2000): In the expected (but non-occurring) unmetathesized form (VʃkC), the stop would be flanked by consonants and thus, be in a context with poor perceptual cues (absence of vowel formant transitions, potential absence of release burst, compressed duration (masking) of phonetic cues). Metathesis serves to improve the global perceptibility of the context; reversing the order of the fricative and stop positions the weaker stop in a more robust context, i.e. post-vocalic. The gain in perceptibility achieved by moving the stop to postvocalic position outweighs any potential loss incurred by shifting the fricative to interconsonantal position. Given the fricative's stonger internal cues, it fares better in interconsonantal position.

Nasal metathesis: Perceptual enhancement (Hume 1997, 1998). In forms such as klum̃pa, kriñta, tiñka, if metathesis does not apply, the stem-final obstruent consonant would occur in preconsonant position. Shifting the obstruent consonant by metathesis to prevocalic position serves to enhance the perceptibility of the consonant, given the presence of the release burst and vowel transition. In the case of nasals, nasal murmur and weak formant structure provide strong cues to both place and manner of articulation. Also, anticipatory coarticulation in the form of vowel nasalization on a preceding vowel provides strong cues to the nasal manner.