Language.Unknown can be treated as a generic Universal language when splitting a GrammaticRelation in text form to make a new relation. After all, the code that puts it back together will use : as the separator anyway for Unknown

Author: AngledLuffa

src/edu/stanford/nlp/trees/GrammaticalRelation.java

@@ -227,7 +227,7 @@ public static GrammaticalRelation valueOf(Language language, String s) {
       */
       String name;
       String specific;
-      char separator = language == Language.UniversalEnglish ? ':' : '_';
+      char separator = (language == Language.UniversalEnglish || language == Language.Unknown) ? ':' : '_';
       int underscorePosition = s.indexOf(separator);
       if (underscorePosition > 0) {
         name = s.substring(0, underscorePosition);