Sõnād nȭrka ja viš astām / The weak and strong grades of words

Livonian gradation or grade alternation refers to the regular stem alternation, which occurs when words change in the stressed syllable and the following syllable. This alternation is usually considered to be the alternation of the weak and strong grades. Both nouns and verbs are subject to grade alternation, e.g.,

Weak grade	Strong grade
kalād ’fish (pl nom)’	ka’llõ ’fish (prt)’
kikīd ’roosters’	kik ’rooster’
liepād ’alders’	lieppõ ’alder (prt)’
kīraz ’ax’	kirrõ ’ax (prt)’
võtāb ’(I) take, (s/he) takes’	võttõ ’to take’
siegūb ’(I) mix, (s/he) mixes’	sie’ggõ ’to mix’

Livonian gradation has been extensively studied by Professor Tiit-Rein Viitso. See, for example, his 2007 article in Linguistica Uralica (LU 2007 XLIII 1, pgs. 23-28).