diff --git a/dlls/mlang/mlang.c b/dlls/mlang/mlang.c
index 42da54e..a60ad70 100644
--- a/dlls/mlang/mlang.c
+++ b/dlls/mlang/mlang.c
@@ -784,6 +784,16 @@
     return hr;
 }
 
+HRESULT WINAPI Rfc1766ToLcidA(LCID *lcid, LPCSTR rfc1766A)
+{
+    WCHAR rfc1766W[MAX_RFC1766_NAME + 1];
+
+    MultiByteToWideChar(CP_ACP, 0, rfc1766A, -1, rfc1766W, MAX_RFC1766_NAME);
+    rfc1766W[MAX_RFC1766_NAME] = 0;
+
+    return Rfc1766ToLcidW(lcid, rfc1766W);
+}
+
 /******************************************************************************
  * MLANG ClassFactory
  */
diff --git a/dlls/mlang/mlang.spec b/dlls/mlang/mlang.spec
index d087b3c..1e8f022 100644
--- a/dlls/mlang/mlang.spec
+++ b/dlls/mlang/mlang.spec
@@ -10,5 +10,5 @@
 @ stdcall IsConvertINetStringAvailable(long long)
 @ stdcall LcidToRfc1766A(long ptr long)
 @ stdcall LcidToRfc1766W(long ptr long)
-@ stub Rfc1766ToLcidA
+@ stdcall Rfc1766ToLcidA(ptr str)
 @ stdcall Rfc1766ToLcidW(ptr wstr)