In this theory , grammars for natural languages are constructed by ranking certain constraints .
( in a phenomenon called factorial typology ) the number of different grammars that can be formed in this way is limited to the number of permutations of the constraints .
In this theory , grammars for natural languages are constructed by ranking certain constraints , and ( in a phenomenon called factorial typology ) the number of different grammars that can be formed in this way is limited to the number of permutations of the constraints .