diff --git a/src/common/tts/TTSPiece.es6 b/src/common/tts/TTSPiece.es6
index b41a823..45eef8e 100644
--- a/src/common/tts/TTSPiece.es6
+++ b/src/common/tts/TTSPiece.es6
@@ -129,9 +129,24 @@ export default class TTSPiece {
             valid = false;
             break;
           }
-          if (el && el.nodeType === Node.ELEMENT_NODE && el.innerText.trim().length === 0) {
-            valid = false;
-            break;
+          if (el && el.nodeType === Node.ELEMENT_NODE) {
+            if (el._cachedEmptyState !== undefined) {
+              if (el._cachedEmptyState === true) {
+                valid = false;
+                break;
+              }
+            } else {
+              try {
+                const isEmpty = el.innerText.trim().length === 0;
+                el._cachedEmptyState = isEmpty;
+                if (isEmpty) {
+                  valid = false;
+                  break;
+                }
+              } catch (e) {
+                el._cachedEmptyState = false;
+              }
+            }
           }
           // 이미지, 독음(후리가나)과 첨자는 읽지 않는다
           if (!(valid = (['RT', 'RP', 'SUB', 'SUP', 'IMG'].indexOf(el.nodeName) === -1))) {