diff --git a/egs/tedlium3/ASR/local/prepare_lexicon.py b/egs/tedlium3/ASR/local/prepare_lexicon.py
index 59377b5aa..35dd332e8 100755
--- a/egs/tedlium3/ASR/local/prepare_lexicon.py
+++ b/egs/tedlium3/ASR/local/prepare_lexicon.py
@@ -23,8 +23,8 @@ consisting of supervisions_train.json and does the following:
 1. Generate lexicon_words.txt.
 
 """
+import lhotse
 import argparse
-import json
 import logging
 from pathlib import Path
 
@@ -60,20 +60,17 @@ def prepare_lexicon(manifests_dir: str, lang_dir: str):
     """
     words = set()
 
-    supervisions_train = Path(manifests_dir) / "supervisions_train.json"
     lexicon = Path(lang_dir) / "lexicon_words.txt"
+    sups = lhotse.load_manifest(
+        f"{manifests_dir}/tedlium_supervisions_train.jsonl.gz"
+    )
+    for s in sups:
+        # list the words units and filter the empty item
+        words_list = list(filter(None, s.text.split()))
 
-    logging.info(f"Loading {supervisions_train}!")
-    with open(supervisions_train, "r") as load_f:
-        load_dicts = json.load(load_f)
-        for load_dict in load_dicts:
-            text = load_dict["text"]
-            # list the words units and filter the empty item
-            words_list = list(filter(None, text.split()))
-
-            for word in words_list:
-                if word not in words and word != "<unk>":
-                    words.add(word)
+        for word in words_list:
+            if word not in words and word != "<unk>":
+                words.add(word)
 
     with open(lexicon, "w") as f:
         for word in sorted(words):
diff --git a/egs/tedlium3/ASR/local/prepare_transcripts.py b/egs/tedlium3/ASR/local/prepare_transcripts.py
index 416264ea0..1039ac5bb 100755
--- a/egs/tedlium3/ASR/local/prepare_transcripts.py
+++ b/egs/tedlium3/ASR/local/prepare_transcripts.py
@@ -23,8 +23,8 @@ consisting of supervisions_train.json and does the following:
 1. Generate train.text.
 
 """
+import lhotse
 import argparse
-import json
 import logging
 from pathlib import Path
 
@@ -60,15 +60,12 @@ def prepare_transcripts(manifests_dir: str, lang_dir: str):
     """
     texts = []
 
-    supervisions_train = Path(manifests_dir) / "supervisions_train.json"
     train_text = Path(lang_dir) / "train.text"
-
-    logging.info(f"Loading {supervisions_train}!")
-    with open(supervisions_train, "r") as load_f:
-        load_dicts = json.load(load_f)
-        for load_dict in load_dicts:
-            text = load_dict["text"]
-            texts.append(text)
+    sups = lhotse.load_manifest(
+        f"{manifests_dir}/tedlium_supervisions_train.jsonl.gz"
+    )
+    for s in sups:
+        texts.append(s.text)
 
     with open(train_text, "w") as f:
         for text in texts: