Front vowels were finally preserved only in the second syllables before they were completely replaced with their back counterparts e.g. käsku ('order, demand' in Lüganuse dialect < *käskü ) or süö-Du ('eaten' in Lüganuse dialect < *süö-Dü ).
e may have substituted ä in some words  e.g. lüpseDä ('to milk (a cow)' in Lüganuse dialect < lüpsäDä).
ä may have falsely substituted a following a syllable, which includes e or i, even though the stem could have back vowels  e.g. ammasteGä ('with teeth' in Lüganuse dialect), e̮liväD ('they were').
ä may have substituted even e of the second syllable, if the first syllable includes ä or ü e.g. üläs ('upwards' in Lüganuse dialect < üles) or pǟlä ('onto' in Lüganuse dialect < *pǟlle ).
ü may have been substituted by iin the second syllable of a stem, if the first syllable includes a short ü e.g. tüli ('quarrel' in Lüganuse dialect) or püssiD ('guns' in Lüganuse dialect < *püssüD ).
In Lüganuse dialect only the a | ä opposition remained active  e.g. jättäGä ('Leave (it)!') vs. tuoGa ('Bring (it)!') or tüöGä ('with work') vs. maaGa ('with earth').
The u | ü opposition has left only rudiments  e.g. küsütti ('it was asked') or kinniDettüD ('fixed').