diff --git a/dlls/msctf/context.c b/dlls/msctf/context.c
index 593f0ad33a3..17396ef7957 100644
--- a/dlls/msctf/context.c
+++ b/dlls/msctf/context.c
@@ -72,6 +72,17 @@ typedef struct tagContext {
 
 } Context;
 
+
+typedef struct tagTextStoreACPSink {
+    const ITextStoreACPSinkVtbl *TextStoreACPSinkVtbl;
+    LONG refCount;
+
+    Context *pContext;
+} TextStoreACPSink;
+
+
+static HRESULT TextStoreACPSink_Constructor(ITextStoreACPSink **ppOut, Context *pContext);
+
 static inline Context *impl_from_ITfSourceVtbl(ITfSource *iface)
 {
     return (Context *)((char *)iface - FIELD_OFFSET(Context,SourceVtbl));
@@ -416,3 +427,149 @@ HRESULT Context_Constructor(TfClientId tidOwner, IUnknown *punk, ITfContext **pp
 
     return S_OK;
 }
+
+/**************************************************************************
+ *  ITextStoreACPSink
+ **************************************************************************/
+
+static void TextStoreACPSink_Destructor(TextStoreACPSink *This)
+{
+    TRACE("destroying %p\n", This);
+    HeapFree(GetProcessHeap(),0,This);
+}
+
+static HRESULT WINAPI TextStoreACPSink_QueryInterface(ITextStoreACPSink *iface, REFIID iid, LPVOID *ppvOut)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    *ppvOut = NULL;
+
+    if (IsEqualIID(iid, &IID_IUnknown) || IsEqualIID(iid, &IID_ITextStoreACPSink))
+    {
+        *ppvOut = This;
+    }
+
+    if (*ppvOut)
+    {
+        IUnknown_AddRef(iface);
+        return S_OK;
+    }
+
+    WARN("unsupported interface: %s\n", debugstr_guid(iid));
+    return E_NOINTERFACE;
+}
+
+static ULONG WINAPI TextStoreACPSink_AddRef(ITextStoreACPSink *iface)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    return InterlockedIncrement(&This->refCount);
+}
+
+static ULONG WINAPI TextStoreACPSink_Release(ITextStoreACPSink *iface)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    ULONG ret;
+
+    ret = InterlockedDecrement(&This->refCount);
+    if (ret == 0)
+        TextStoreACPSink_Destructor(This);
+    return ret;
+}
+
+/*****************************************************
+ * ITextStoreACPSink functions
+ *****************************************************/
+
+static HRESULT WINAPI TextStoreACPSink_OnTextChange(ITextStoreACPSink *iface,
+        DWORD dwFlags, const TS_TEXTCHANGE *pChange)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    FIXME("STUB:(%p)\n",This);
+    return E_NOTIMPL;
+}
+
+static HRESULT WINAPI TextStoreACPSink_OnSelectionChange(ITextStoreACPSink *iface)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    FIXME("STUB:(%p)\n",This);
+    return E_NOTIMPL;
+}
+
+static HRESULT WINAPI TextStoreACPSink_OnLayoutChange(ITextStoreACPSink *iface,
+    TsLayoutCode lcode, TsViewCookie vcView)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    FIXME("STUB:(%p)\n",This);
+    return E_NOTIMPL;
+}
+
+static HRESULT WINAPI TextStoreACPSink_OnStatusChange(ITextStoreACPSink *iface,
+        DWORD dwFlags)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    FIXME("STUB:(%p)\n",This);
+    return E_NOTIMPL;
+}
+
+static HRESULT WINAPI TextStoreACPSink_OnAttrsChange(ITextStoreACPSink *iface,
+        LONG acpStart, LONG acpEnd, ULONG cAttrs, const TS_ATTRID *paAttrs)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    FIXME("STUB:(%p)\n",This);
+    return E_NOTIMPL;
+}
+
+static HRESULT WINAPI TextStoreACPSink_OnLockGranted(ITextStoreACPSink *iface,
+        DWORD dwLockFlags)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    FIXME("STUB:(%p)\n",This);
+    return E_NOTIMPL;
+}
+
+static HRESULT WINAPI TextStoreACPSink_OnStartEditTransaction(ITextStoreACPSink *iface)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    FIXME("STUB:(%p)\n",This);
+    return E_NOTIMPL;
+}
+
+static HRESULT WINAPI TextStoreACPSink_OnEndEditTransaction(ITextStoreACPSink *iface)
+{
+    TextStoreACPSink *This = (TextStoreACPSink *)iface;
+    FIXME("STUB:(%p)\n",This);
+    return E_NOTIMPL;
+}
+
+static const ITextStoreACPSinkVtbl TextStoreACPSink_TextStoreACPSinkVtbl =
+{
+    TextStoreACPSink_QueryInterface,
+    TextStoreACPSink_AddRef,
+    TextStoreACPSink_Release,
+
+    TextStoreACPSink_OnTextChange,
+    TextStoreACPSink_OnSelectionChange,
+    TextStoreACPSink_OnLayoutChange,
+    TextStoreACPSink_OnStatusChange,
+    TextStoreACPSink_OnAttrsChange,
+    TextStoreACPSink_OnLockGranted,
+    TextStoreACPSink_OnStartEditTransaction,
+    TextStoreACPSink_OnEndEditTransaction
+};
+
+static HRESULT TextStoreACPSink_Constructor(ITextStoreACPSink **ppOut, Context *pContext)
+{
+    TextStoreACPSink *This;
+
+    This = HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY,sizeof(TextStoreACPSink));
+    if (This == NULL)
+        return E_OUTOFMEMORY;
+
+    This->TextStoreACPSinkVtbl= &TextStoreACPSink_TextStoreACPSinkVtbl;
+    This->refCount = 1;
+
+    This->pContext = pContext;
+
+    TRACE("returning %p\n", This);
+    *ppOut = (ITextStoreACPSink*)This;
+    return S_OK;
+}
diff --git a/include/textstor.idl b/include/textstor.idl
index f9624f6a0f5..86a01e0a1e5 100644
--- a/include/textstor.idl
+++ b/include/textstor.idl
@@ -35,3 +35,49 @@ typedef [uuid(fec4f516-c503-45b1-a5fd-7a3d8ab07049)] struct TS_STATUS
     DWORD dwDynamicFlags;
     DWORD dwStaticFlags;
 } TS_STATUS;
+
+typedef [uuid(f3181bd6-bcf0-41d3-a81c-474b17ec38fb)]  struct TS_TEXTCHANGE
+{
+    LONG acpStart;
+    LONG acpOldEnd;
+    LONG acpNewEnd;
+} TS_TEXTCHANGE;
+
+typedef [uuid(ef3457d9-8446-49a7-a9e6-b50d9d5f3fd9)]  GUID TS_ATTRID;
+typedef [uuid(7899d7c4-5f07-493c-a89a-fac8e777f476)]  enum { TS_LC_CREATE, TS_LC_CHANGE, TS_LC_DESTROY } TsLayoutCode;
+typedef [uuid(1faf509e-44c1-458e-950a-38a96705a62b)]  DWORD TsViewCookie;
+
+
+[
+  object,
+  uuid(22d44c94-a419-4542-a272-ae26093ececf),
+  pointer_default(unique)
+]
+interface ITextStoreACPSink : IUnknown
+{
+    HRESULT OnTextChange(
+        [in] DWORD dwFlags,
+        [in] const TS_TEXTCHANGE *pChange);
+
+    HRESULT OnSelectionChange();
+
+    HRESULT OnLayoutChange(
+        [in] TsLayoutCode lcode,
+        [in] TsViewCookie vcView);
+
+    HRESULT OnStatusChange(
+        [in] DWORD dwFlags);
+
+    HRESULT OnAttrsChange(
+        [in] LONG acpStart,
+        [in] LONG acpEnd,
+        [in] ULONG cAttrs,
+        [in, size_is(cAttrs)] const TS_ATTRID *paAttrs);
+
+    HRESULT OnLockGranted(
+        [in] DWORD dwLockFlags);
+
+    HRESULT OnStartEditTransaction();
+
+    HRESULT OnEndEditTransaction();
+};