diff --git a/include/cppjieba/DictTrie.hpp b/include/cppjieba/DictTrie.hpp
index 3478db4..97b4643 100644
--- a/include/cppjieba/DictTrie.hpp
+++ b/include/cppjieba/DictTrie.hpp
@@ -198,7 +198,7 @@ class DictTrie {
         double weight, 
         const string& tag) {
     if (!DecodeUTF8RunesInString(word, node_info.word)) {
-      XLOG(ERROR) << "Decode " << word << " failed.";
+      XLOG(ERROR) << "UTF-8 decode failed for dict word: " << word;
       return false;
     }
     node_info.weight = weight;
diff --git a/include/cppjieba/PosTagger.hpp b/include/cppjieba/PosTagger.hpp
index a6810b2..1586330 100644
--- a/include/cppjieba/PosTagger.hpp
+++ b/include/cppjieba/PosTagger.hpp
@@ -35,7 +35,7 @@ class PosTagger {
     const DictTrie * dict = segment.GetDictTrie();
     assert(dict != NULL);
       if (!DecodeUTF8RunesInString(str, runes)) {
-        XLOG(ERROR) << "Decode failed.";
+        XLOG(ERROR) << "UTF-8 decode failed for word: " << str;
         return POS_X;
       }
       tmp = dict->Find(runes.begin(), runes.end());
diff --git a/include/cppjieba/PreFilter.hpp b/include/cppjieba/PreFilter.hpp
index e73b9ab..deb750b 100644
--- a/include/cppjieba/PreFilter.hpp
+++ b/include/cppjieba/PreFilter.hpp
@@ -18,7 +18,7 @@ class PreFilter {
         const string& sentence)
     : symbols_(symbols) {
     if (!DecodeUTF8RunesInString(sentence, sentence_)) {
-      XLOG(ERROR) << "decode failed. "; 
+      XLOG(ERROR) << "UTF-8 decode failed for input sentence"; 
     }
     cursor_ = sentence_.begin();
   }
diff --git a/include/cppjieba/SegmentBase.hpp b/include/cppjieba/SegmentBase.hpp
index 2885b83..130b212 100644
--- a/include/cppjieba/SegmentBase.hpp
+++ b/include/cppjieba/SegmentBase.hpp
@@ -26,7 +26,7 @@ class SegmentBase {
     symbols_.clear();
     RuneStrArray runes;
     if (!DecodeUTF8RunesInString(s, runes)) {
-      XLOG(ERROR) << "decode " << s << " failed";
+      XLOG(ERROR) << "UTF-8 decode failed for separators: " << s;
       return false;
     }
     for (size_t i = 0; i < runes.size(); i++) {