diff --git a/faster_whisper/transcribe.py b/faster_whisper/transcribe.py
index 9c84309..273042a 100644
--- a/faster_whisper/transcribe.py
+++ b/faster_whisper/transcribe.py
@@ -668,8 +668,8 @@ def merge_punctuations(alignment: List[dict], prepended: str, appended: str):
         following = alignment[j]
         if previous["word"].startswith(" ") and previous["word"].strip() in prepended:
             # prepend it to the following word
-            following["word"] = previous.word + following.word
-            following["tokens"] = previous.tokens + following.tokens
+            following["word"] = previous["word"] + following["word"]
+            following["tokens"] = previous["tokens"] + following["tokens"]
             previous["word"] = ""
             previous["tokens"] = []
         else: