1. A method comprising: receiving at a computing node an input sequence comprising a plurality of tokens; applying by a processor of the computing node a plurality of domain-specific generators to the input sequence to generate a set of candidate replacements of the tokens of the input sequence; creating in a memory of the computing node a directed graph comprising a plurality of nodes and a plurality of edges, each node having an associated candidate replacement of the set of candidate replacements, and each edge connecting a first node to a second node, the second node being associated with a consistent follower of the candidate replacement associated with the first node, and creating the plurality of edges comprising determining syntactic consistency between each pair of the set of candidate replacements; determining by the processor a plurality of paths in the directed graph, each of the plurality of paths comprising at least one of the plurality of edges; determining by the processor a score for each of the paths; selecting by the processor a path of the plurality of paths having the highest score; applying by the processor each candidate replacement of the selected path to the input sequence to generate a normalized output sequence; and evaluating a correctness of the normalized output sequence by parsing the normalized output sequence to obtain a parse result and comparing the parse result with a gold standard that is obtained by parsing a manually normalized sequence.