uses
  TypInfo, IniFiles;

var
  apppath: string;

function MyGetWideStrProp(Instance: TObject; const PropName: string): Widestring;
var
  PropInfo: PPropInfo;
begin
  PropInfo := GetPropInfo(Instance, PropName);
  if PropInfo = NIL then
  begin
    raise EPropertyError.CreateResFmt(@SUnknownProperty, [PropName]);
  end;
  result := GetWideStrProp(Instance, PropName);
end;

procedure MySetWideStrProp(Instance: TObject; const PropName: string; const Value: Widestring);

var
  PropInfo: PPropInfo;
begin
  PropInfo := GetPropInfo(Instance, PropName);
  if PropInfo = NIL then
  begin
    raise EPropertyError.CreateResFmt(@SUnknownProperty, [PropName]);
  end;
  SetWideStrProp(Instance, PropInfo, Value);
end;

procedure WriteIni(aForm: TForm; aType: TClass; const aProperty: string = 'Text');
var
  CurrentCompo: TComponent;
  ndx: Integer;
  TranslateIni: TMemIniFile;
  CurrentText: string;
begin
  TranslateIni := TMemIniFile.Create(apppath + 'default.lng');
  try
    for ndx := 0 to Pred(aForm.ComponentCount) do
    begin
      CurrentCompo := aForm.Components[ndx];
      if (CurrentCompo is aType) then
      begin
        CurrentText := MyGetWideStrProp(CurrentCompo, aProperty);
        TranslateIni.WriteString(CurrentCompo.ClassName + '-' + aProperty,
          CurrentCompo.Name, CurrentText);
      end;
    end;
    TranslateIni.UpdateFile;
  finally
    TranslateIni.Free;
  end;
end;

procedure ReadIni(aForm: TForm; aType: TClass; const aProperty: string = 'Text');
var
  CurrentCompo: TComponent;
  ndx: Integer;
  TranslateIni: TMemIniFile;
  NewText: string;
begin
  TranslateIni := TMemIniFile.Create(apppath + 'default.lng');
  try
    for ndx := 0 to Pred(aForm.ComponentCount) do
    begin
      CurrentCompo := aForm.Components[ndx];
      if (CurrentCompo is aType) then
      begin
        NewText := TranslateIni.ReadString(CurrentCompo.ClassName + '-' +
          aProperty, CurrentCompo.Name, '');
        MySetWideStrProp(CurrentCompo, aProperty, NewText);
      end;
    end;
  finally
    TranslateIni.Free;
  end;
end;

procedure TDemoForm.FormCreate(Sender: TObject);
begin
  apppath := IncludeTrailingBackslash(ExtractFilePath(ParamStr(0)));
  ReadIni(self, TEdit, 'Text');
  ReadIni(self, TLabel, 'Caption');
end;


procedure TDemoForm.FormDestroy(Sender: TObject);
begin
  WriteIni(self, TEdit, 'Text');
  WriteIni(self, TLabel, 'Caption');
end;

[TEdit-Text]
Edit1=Ein Text
Edit2=noch einer
Edit3=
Edit4=*blubb*
[TLabel-Caption]
Label1=Ich bin ein Label
Label2=Ich auch
Label3=*blubb*