protected String normalize(String input) {
        if (input == null || input.length() == 0) return input;

        return environment.getLinguistics().getNormalizer().normalize(input);
    }
Unicode normalizes some piece of natural language text. The chosen form
is compatibility decomposition, canonical composition (NFKC).
container-search/src/main/java/com/yahoo/prelude/query/parser/AbstractParser.java