diff --git a/lib/utils/tts-streaming-buffer.js b/lib/utils/tts-streaming-buffer.js
index b397aeeb..6745121f 100644
--- a/lib/utils/tts-streaming-buffer.js
+++ b/lib/utils/tts-streaming-buffer.js
@@ -437,7 +437,15 @@ class TtsStreamingBuffer extends Emitter {
 
 const findSentenceBoundary = (text, limit) => {
   // Look for punctuation or double newline that signals sentence end.
-  const sentenceEndRegex = /[.!?](?=\s|$)|\n\n/g;
+  // Includes:
+  //   - ASCII: . ! ?
+  //   - Arabic: ؟ (question mark), ۔ (full stop)
+  //   - Japanese: 。 (full stop), ！, ？ (full-width exclamation/question)
+  //
+  // For languages that use spaces between sentences, we still require
+  // whitespace or end-of-string after the mark. For Japanese (no spaces),
+  // we treat the punctuation itself as a boundary regardless of following char.
+  const sentenceEndRegex = /[.!?؟۔](?=\s|$)|[。！？]|\n\n/g;
   let lastSentenceBoundary = -1;
   let match;
   while ((match = sentenceEndRegex.exec(text)) && match.index < limit) {