diff --git a/Source/Utility/LexiconBoundary.cpp b/Source/Utility/LexiconBoundary.cpp
new file mode 100644
index 0000000..9d5b746
--- /dev/null
+++ b/Source/Utility/LexiconBoundary.cpp
@@ -0,0 +1,38 @@
+#include "Utility/LexiconBoundary.h"
+
+// FUNCTION: fn_17634
+bool LexiconBoundary::Matches(unsigned char previous, unsigned char current, unsigned char options) const {
+  if (previous == 0xDD) {
+    return true;
+  }
+
+  if ((this->flags[previous] & 1) != 0 && (this->flags[current] & 0x2100) != 0) {
+    return true;
+  }
+
+  if (current == 32) {
+    return true;
+  }
+
+  if (previous == 32) {
+    return false;
+  }
+
+  const std::uint32_t before = this->flags[previous];
+  const std::uint32_t after = this->flags[current];
+  if ((options & 2) != 0) {
+    return ((before & 0x470) != 0) == ((after & 0x470) != 0) &&
+           (((before & 0x1000) != 0 && (after & 1) != 0) || ((before & 0x470) != 0 && (after & 0x470) != 0) ||
+            ((before & 2) != 0 && (after & 2) != 0));
+  }
+
+  if ((after & 0x10) != 0 && (before & 0x10) == 0) {
+    return false;
+  }
+
+  if ((after & 0x60) != 0 || (before & 0x10) != 0 || ((before & 0x1000) != 0 && (after & 1) != 0)) {
+    return true;
+  }
+
+  return ((before & 0x400) != 0 && (after & 0x10002) != 0) || (after & 0x400) != 0;
+}
diff --git a/Source/Utility/LexiconBoundary.h b/Source/Utility/LexiconBoundary.h
new file mode 100644
index 0000000..fd56eac
--- /dev/null
+++ b/Source/Utility/LexiconBoundary.h
@@ -0,0 +1,13 @@
+#ifndef RAGNAROK_SOURCE_UTILITY_LEXICONBOUNDARY_H
+#define RAGNAROK_SOURCE_UTILITY_LEXICONBOUNDARY_H
+
+#include <cstdint>
+
+struct LexiconBoundary {
+  /* 0000 */ std::uint32_t unknown_0000;
+  /* 0004 */ std::uint32_t flags[256];
+
+  bool Matches(unsigned char previous, unsigned char current, unsigned char options) const;
+};
+
+#endif
diff --git a/compile.json b/compile.json
index b079dcb..25040fc 100644
--- a/compile.json
+++ b/compile.json
@@ -582,6 +582,7 @@
   "Source/Utility/Async/NRecycleObjectPoolMgr.cpp": 0,
   "Source/Utility/Base64.cpp": 0,
   "Source/Utility/GuidParse.cpp": 0,
+  "Source/Utility/LexiconBoundary.cpp": 0,
   "Source/Utility/MD5.cpp": 0,
   "Source/Utility/Math/AffineLookAt.cpp": 0,
   "Source/Utility/Math/AffineMatrix.cpp": 0,