sS englishToConceptLanguage_xyz(S s, O preprocess) {
  assertNotNull("Input", s);
  s = postProcess(preprocess, s);
  
  // pattern matching all concepts against full string
  Map<S, AIConcept> concepts = aiConceptsMap_cached();
  
  new Matches m;
  for (AIConcept c : values(concepts)) {
    if (empty(c.name)) {
      print("Warning, empty name: " + c.globalID);
      continue;
    }
    S name = postProcess(preprocess, c.name);
    L<S> tok = javaTokC(name);
    int iX = tok.indexOf("X");
    if (iX >= 0) {
      int iY = tok.indexOf("Y");
      if (iY >= 0) {
        S pat = formatXYZ(name, "*", "*");
        bool complicated = containsSubList(tok, "X", "Y");
        if (complicated ? jmatch(pat, s, m) : flexMatchIC(pat, s, m)) {
          assertEquals(name, 2, l(m.m));
          S a = englishToConceptLanguage_xyz_sub($1);
          S b = englishToConceptLanguage_xyz_sub($2);
          ret c.globalID + " " +
            (iX < iY ? a + " " + b : b + " " + a);
        }
      } else {
        S pat = formatXYZ(name, "*");
        if (flexMatchIC(pat, s, m)) {
          assertEquals(name, 1, l(m.m));
          S a = englishToConceptLanguage_xyz_sub($1);
          ret c.globalID + " " + a;
        }
      }
    }
  }
  
  // no full string match. go word by word
  L<S> tok = javaTok(s);
  if (l(tok) <= 3) null;
  for (int i = 1; i < l(tok); i += 2) {
    S x = englishToConceptLanguage(unquote(tok.get(i)));
    if (nempty(x)) tok.set(i, conceptQuote(x));
  }
  S x = join(tok);
  ret eq(x, s) ? null : x;
}

sS englishToConceptLanguage_xyz_sub(S s) {
  ret conceptQuote(or2(englishToConceptLanguage(s), s));
}