diff --git a/src/laion_clap/training/data.py b/src/laion_clap/training/data.py
index 765db7c..3fd9a62 100644
--- a/src/laion_clap/training/data.py
+++ b/src/laion_clap/training/data.py
@@ -41,9 +41,9 @@
 except ImportError:
     torchaudio = None
 
-bert_tokenizer = BertTokenizer.from_pretrained("bert-base-uncased")
-roberta_tokenizer = RobertaTokenizer.from_pretrained("roberta-base")
-bart_tokenizer = BartTokenizer.from_pretrained("facebook/bart-base")
+bert_tokenizer = None
+roberta_tokenizer = None
+bart_tokenizer = None
 
 def tokenizer(text, tmodel="roberta", max_length=77):
     """tokenizer for different models
@@ -51,10 +51,12 @@ def tokenizer(text, tmodel="roberta", max_length=77):
     max_length is default to 77 from the OpenAI CLIP parameters
     We assume text to be a single string, but it can also be a list of strings
     """
+    global bert_tokenizer, roberta_tokenizer, bart_tokenizer
     if tmodel == "transformer":
         return clip_tokenizer(text).squeeze(0)
-
     elif tmodel == "bert":
+        if bert_tokenizer is None:
+            bert_tokenizer = BertTokenizer.from_pretrained("bert-base-uncased")
         result = bert_tokenizer(
             text,
             padding="max_length",
@@ -63,8 +65,9 @@ def tokenizer(text, tmodel="roberta", max_length=77):
             return_tensors="pt",
         )
         return {k: v.squeeze(0) for k, v in result.items()}
-
     elif tmodel == "roberta":
+        if roberta_tokenizer is None:
+            roberta_tokenizer = RobertaTokenizer.from_pretrained("roberta-base")
         result = roberta_tokenizer(
             text,
             padding="max_length",
@@ -73,8 +76,9 @@ def tokenizer(text, tmodel="roberta", max_length=77):
             return_tensors="pt",
         )
         return {k: v.squeeze(0) for k, v in result.items()}
-
     elif tmodel == "bart":
+        if bart_tokenizer is None:
+            bart_tokenizer = BartTokenizer.from_pretrained("facebook/bart-base")
         result = bart_tokenizer(
             text,
             padding="max_length",