The indefinite voice describes an action without giving any information about it's agent. Hence a present tense indefinite expression like juvvaz could be translated approximately as: "Somebody drinks!". We don't bother ourselves clarifying, who is drinking.
The suffix -t'aksen has been replaced with -tā or -tǟ (influenced by Ingrian dialects) e.g. лauлo+t'aksen > лauлotā ('Somebody sings') vs. tšüsü+t'aksen > tšüzütǟ ('Somebody asks' )
In front of any indefinite voice marker the stem-vowela alternates with e̮ and ä alternates with e e.g. levvetǟ ('Somebody finds' vs. levvä - the 2. person's singular imperative). This example is composed for Wikiversity and needs verification.
The suffix -t'aksen has became -tasse or -tas̆se (after an unstressed syllable) e.g. tuo+t'aksen > tuasse ('Somebody brings' ) - Lüganuse dialect vs. tuo+t'aksen > tūvas̆se ('Somebody brings' ) - Iisaku dialect
The suffix -t'aksen may substitute -t'ak suffix by negation e.g. epi tuo+t'aksen > ei tuvas̆se ('Nobody brings' ) - Lüganuse dialect
Verbal stem is always in the weak grade in front of any indefinite voice marker e.g. keittä+t'aksen > keitet̆tässe ('Somebody boils').
The suffix -t'aksen may have been replaced with -ta or -Da (possibly influenced by Estonian coastal dialects) e.g. vestä+t'aksen > vestetä ('Somebody whittles') 
The suffix -t'aksen may have been replaced with -tta or -t̆ta (after an unstressed syllable) (possibly influenced by Estonian coastal dialects) e.g. kisku+t'aksen > kisut̆ta ('Somebody tears' )
The -ta component of the suffix has usually been assimilated with preceding dental consonants: l, n, r, s, t like the -takinfinitive e.g. me̮ttel+t'aksen > me̮ella ('Somebody thinks'), pes+t'aksen > pessäs̆se ('Somebody washes') - Lüganuse dialect.
The -ta component of the suffix will be assimilated also with preceding stressed long (labialized) vowels and diphtongs: uo, ū, üö, ǖ like the -takinfinitive producing