5.1. Invariancy (nonalternation)

	Finn.	Seto	Er.	HMr	MMr	Ud.	Hun.	SMn	SKh	VKh	Nga.	Ka.
F/B.	i, e	i	i, ɑ	i, e	i, e, ɑ, ə̆	i, e, o, ɑ, ɘ̆	i(ː), eː, ɛ	?	i, e	0	all	i
R\|T	–	–	–	–	i, e, ɑ, ə̆	–	all but o, ø	?	–	–	ɘ, ɑ, i̯ɑ, u̯ɑ	all but ə̆

Finnish, Seto, Hill Mari, Hungarian F/B, Vakh/Vasyugan Khanty, Kamas F/B harmony: Unrounded front vowels having no back counterpart do not undergo harmony but can follow both back-harmonic and front-harmonic vowels. In the case of Vakh/Vasyugan Khanty, /e/ has no back counterpart, but it does not occur in non-initial syllables.

Hungarian rounding harmony: Since only three vowels can undergo harmony (/ɛ/ : /ø/ : /o/) but /ɛ/ also participates in another alternation (/ɛ/ : /ɒ/), only the distribution of /ø/ and /o/ is restricted by harmony.

Kamas total harmony: Since the only target of total harmony can be /ə̆/, any other vowel can follow another vowel. (However, rounded vowels seem to occur typically after other rounded vowels, further investigation needed.)

Erzya: /ɑ/ has no front counterpart but frequently occurs after front vowels. /i/ is rare in non-initial vowels, although it occurs in verbal suffixes. /u/ is rare in non-initial syllables, and it never occurs in suffixes.

Meadow Mari: Since only the word-final vowel undergoes harmony, the vowel of the initial syllable can be followed by any vowel which may occur in non-initial syllables (i.e. any unrounded vowel).

Southern Khanty: The vowels /i/ and /e/ have no back counterparts: they can follow both front and back vowels, although after the latter they can undergo harmony allophonically.

Nganasan quasi-rounding harmony: All the harmonic vowels are reported to occur in non-alternating suffixes (except for /i̯ɑ/), and stems containing any of the vowels can change suffixes containing alternating allophones belonging to the opposite class, therefore any vowel can follow any other. F/B harmony: Since this harmony is parasitic on high vowels, non-high vowels can follow both front and back vowels.