diff --git a/Source/nlf.cpp b/Source/nlf.cpp
new file mode 100644
index 00000000..ced2da99
--- /dev/null
+++ b/Source/nlf.cpp
@@ -0,0 +1,64 @@
+#include <Windows.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "nlf.h"
+
+char SkipComments(FILE *f) {
+  char c;
+  while (c = fgetc(f))
+    if (c == '#' || c == ';') {
+      while (c = fgetc(f))
+       if (c == '\n') break;
+      }
+    else break;
+  return c;
+}
+
+// NSIS Language File parser
+NLF::NLF(char *filename) {
+  FILE *f = fopen(filename, "r");
+  if (!f) throw runtime_error("Can't open language file!");
+
+  char buf[1024];
+  buf[0] = SkipComments(f);
+  fgets(buf+1, 1024, f);
+
+  // Check header
+  if (strncmp(buf, "NLF v", 5)) throw runtime_error("Invalid language file!");
+  if (atoi(buf+5) != NLF_VERSION) throw runtime_error("Language file version doesn't match NSIS version!");
+
+  // Get language ID
+  buf[0] = SkipComments(f);
+  fgets(buf+1, 1024, f);
+  m_wLangId = atoi(buf);
+
+  // Read strings
+  for (int i = 0; i < NLF_STRINGS; i++) {
+    buf[0] = SkipComments(f);
+    fgets(buf+1, 1024, f);
+    if (lstrlen(buf) == 1023) {
+      wsprintf(buf, "String too long (string #%d)!", i);
+      throw runtime_error(buf);
+    }
+    m_szStrings[i] = new char[lstrlen(buf)+1];
+    lstrcpy(m_szStrings[i], buf);
+  }
+
+  fclose(f);
+}
+
+NLF::~NLF() {
+  MessageBox(0, "destructor", "info", MB_OK);
+  for (int i = 0; i < NLF_STRINGS; i++) {
+    delete [] m_szStrings[i];
+  }
+}
+
+WORD NLF::GetLang() {
+  return m_wLangId;
+}
+
+char* NLF::GetString(int idx) {
+  if (idx < 0 || idx >= NLF_STRINGS) return 0;
+  return m_szStrings[idx];
+}
\ No newline at end of file
diff --git a/Source/nlf.h b/Source/nlf.h
index cee93f35..52753ae7 100644
--- a/Source/nlf.h
+++ b/Source/nlf.h
@@ -1,7 +1,8 @@
 #ifndef ___NLF___H_____
 #define ___NLF___H_____
 
-#include <Windows.h>
+#include <StdExcept>
+using namespace std;
 
 #define NLF_VERSION 1
 #define NLF_STRINGS 57
@@ -64,62 +65,14 @@
 #define NLF_RENAME 55
 #define NLF_SKIPPED 56
 
-char SkipComments(FILE *f) {
-  char c;
-  while (c = fgetc(f))
-    if (c == '#' || c == ';') {
-      while (c = fgetc(f))
-       if (c == '\n') break;
-      }
-    else break;
-  return c;
-}
-
-extern FILE *g_output;
-#define s(x) fprintf(g_output, x"\n"); fflush(g_output);
-#define s2(x,y) fprintf(g_output, x"\n", y); fflush(g_output);
-
 // NSIS Language File parser
 class NLF {
   public:
-    NLF(char *filename) {
-      FILE *f = fopen(filename, "r");
-      if (!f) throw runtime_error("Can't open language file!");
+    NLF(char *filename);
+    ~NLF();
 
-      char buf[1024];
-      buf[0] = SkipComments(f);
-      fgets(buf+1, 1024, f);
-
-      // Check header
-      if (strncmp(buf, "NLF v", 5)) throw runtime_error("Invalid language file!");
-      if (atoi(buf+5) != NLF_VERSION) throw runtime_error("Language file version doesn't match NSIS version!");
-
-      // Get language ID
-      buf[0] = SkipComments(f);
-      fgets(buf+1, 1024, f);
-      m_wLangId = atoi(buf);
-
-      // Read entries
-      int i = 0;
-      while (i < NLF_STRINGS) {
-        buf[0] = SkipComments(f);
-        fgets(buf+1, 1024, f);
-        if (lstrlen(buf) == 1023) {
-          wsprintf(buf, "String too long (string #%d)!", i);
-          throw runtime_error(buf);
-        }
-        //m_szStrings[i] = new char[lstrlen(buf)];
-        m_szStrings[i] = (char*)GlobalAlloc(GPTR, lstrlen(buf));
-        lstrcpy(m_szStrings[i], buf);
-        i++;
-      }
-
-      for (i = 0; i < NLF_STRINGS; i++) {
-        GlobalFree(m_szStrings[i]);
-      }
-
-      fclose(f);
-    }
+    WORD GetLang();
+    char* GetString(int idx);
 
   private:
     WORD m_wLangId;
diff --git a/Source/script.cpp b/Source/script.cpp
index ae104821..90395ba0 100644
--- a/Source/script.cpp
+++ b/Source/script.cpp
@@ -1215,7 +1215,19 @@ int CEXEBuild::doCommand(int which_token, LineParser &line, FILE *fp, const char
     case TOK_LOADNLF:
     {
       SCRIPT_MSG("LoadLanguageFile: %s\n", line.gettoken_str(1));
-      NLF *lang = new NLF(line.gettoken_str(1));
+      try {
+      	NLF *newLang = new NLF(line.gettoken_str(1));
+        for (int i = 0; i < build_langs.size(); i++)
+          if (build_langs[i]->GetLang() == newLang->GetLang()) {
+            ERROR_MSG("Error: Can't add same language twice!\n");
+            return PS_ERROR;
+          }
+        build_langs.push_back(newLang);
+      }
+      catch (exception &err) {
+        ERROR_MSG("Error while adding language file: %s", err.what());
+        return PS_ERROR;
+      }
     }
     return make_sure_not_in_secorfunc(line.gettoken_str(0));