diff --git a/model/model_training/custom_datasets/entities.py b/model/model_training/custom_datasets/entities.py
new file mode 100644
index 0000000000..6aaa63c6a1
--- /dev/null
+++ b/model/model_training/custom_datasets/entities.py
@@ -0,0 +1,7 @@
+from enum import Enum
+
+
+class Mode(Enum):
+    sft = "sft"
+    rm = "rm"
+    rl = "rl"
diff --git a/model/model_training/custom_datasets/formatting.py b/model/model_training/custom_datasets/formatting.py
index 633c1e8306..91e25b513e 100644
--- a/model/model_training/custom_datasets/formatting.py
+++ b/model/model_training/custom_datasets/formatting.py
@@ -1,7 +1,8 @@
 from itertools import zip_longest
 from random import shuffle
 
-from model_training.custom_datasets.entities import Language, Mode
+from langcodes import Language
+from model_training.custom_datasets.entities import Mode
 from pydantic import BaseModel, validator
 from pydantic.fields import ModelField
 
@@ -25,12 +26,19 @@ def format_system_prefix(prefix, eos_token):
 class DatasetEntry(BaseModel):
     questions: list[str]
     answers: list[str]
-    context: str | None
-    lang: Language | None
-    length: int | None
-    quality: float | None
-    humor: float | None
-    creativity: float | None
+    context: str | None = None
+    lang: str | None = None
+    length: int | None = None
+    quality: float | None = None
+    humor: float | None = None
+    creativity: float | None = None
+
+    @validator("lang")
+    def valid_lang(cls, v) -> str | None:
+        if v is not None:
+            if not (lang := Language.get(v)).is_valid():
+                raise ValueError(f"Language {v} is not valid. Please provide BCP 47 compatible language codes.")
+            return str(lang)
 
     @validator("length")
     def above_zero(cls, v) -> int:
diff --git a/model/model_training/tests/test_formatting.py b/model/model_training/tests/test_formatting.py
index 01eb3e6e55..21c9e3ab3f 100644
--- a/model/model_training/tests/test_formatting.py
+++ b/model/model_training/tests/test_formatting.py
@@ -1,5 +1,6 @@
 import pytest
-from model_training.custom_datasets.entities import Language, Mode
+from langcodes import Language
+from model_training.custom_datasets.entities import Mode
 from model_training.custom_datasets.formatting import QA_SPECIAL_TOKENS, DatasetEntry
 
 
@@ -29,7 +30,7 @@ def test_dataset_entry():
         questions=["What is the capital of France?"],
         answers=["The capital of France is Paris."],
         context="Some context",
-        lang=Language("en"),
+        lang="en",
         length=100,
         quality=1.0,
         humor=0.0,
diff --git a/model/pyproject.toml b/model/pyproject.toml
index bc13ff6f81..bca221403a 100644
--- a/model/pyproject.toml
+++ b/model/pyproject.toml
@@ -27,6 +27,7 @@ dependencies = [
     "sentencepiece==0.1.97",
     "scikit-learn==1.2.0",
     "tokenizers==0.13.2",
+    "langcodes==3.3.0",
     "torch==1.13.1",
     "tqdm==4.65.0",
     "pydantic==1.10.7",