diff --git a/spacy/errors.py b/spacy/errors.py
index c86c431ce..7f3c58af7 100644
--- a/spacy/errors.py
+++ b/spacy/errors.py
@@ -957,6 +957,9 @@ class Errors(metaclass=ErrorsWithCodes):
     E4000 = ("Expected a Doc as input, but got: '{type}'")
     E4001 = ("Expected input to be one of the following types: ({expected_types}), "
              "but got '{received_type}'")
+    E4002 = ("Language code defined in config ({bad_lang_code}) does not match "
+            "language code of current Language subclass {lang} ({lang_code}) because it was renamed in v4. "
+            "Please change your current defined language code from ({bad_lang_code}) to ({lang_code}).")
 
 
 # Deprecated model shortcuts, only used in errors and warnings
diff --git a/spacy/language.py b/spacy/language.py
index ca1fad413..fc8993f98 100644
--- a/spacy/language.py
+++ b/spacy/language.py
@@ -1736,13 +1736,24 @@ class Language:
             raise ValueError(Errors.E985.format(config=config))
         config_lang = config["nlp"].get("lang")
         if config_lang is not None and config_lang != cls.lang:
-                raise ValueError(
-                    Errors.E958.format(
-                        bad_lang_code=config["nlp"]["lang"],
-                        lang_code=cls.lang,
-                        lang=util.get_object_name(cls),
+                # Set of language codes that were renamed in v4
+                renamed_lang_codes = set(["xx","is"])
+                if config_lang in renamed_lang_codes:
+                    raise ValueError(
+                        Errors.E4002.format(
+                            bad_lang_code=config["nlp"]["lang"],
+                            lang_code=cls.lang,
+                            lang=util.get_object_name(cls),
+                        )
+                    )
+                else:
+                    raise ValueError(
+                        Errors.E958.format(
+                            bad_lang_code=config["nlp"]["lang"],
+                            lang_code=cls.lang,
+                            lang=util.get_object_name(cls),
+                        )
                     )
-                )
         config["nlp"]["lang"] = cls.lang
         # This isn't very elegant, but we remove the [components] block here to prevent
         # it from getting resolved (causes problems because we expect to pass in