[delphi.com.ar]

¿Puedo contradecirme?
Es algo mas genérico y económico:

Código Delphi [-]
function TranslateChars(const AText, ASource, ADest: string): string;
var
  Ch: Char;
  L, P: Integer;
  Source,
  Dest: PChar;
begin
  L := Length(AText);
  SetLength(Result, L);
  Source := Pointer(AText);
  Dest := Pointer(Result);
  while L <> 0 do
  begin
    Ch := Source^;
    P := Pos(Ch, ASource);
    if P > 0 then
      Dest^ := ADest[P]
    else
      Dest^ := Ch;
    Inc(Source);
    Inc(Dest);
    Dec(L);
  end;
end;

....

procedure TForm1.Button1Click(Sender: TObject);
const
  CHARS_ACENTUADOS = 'ÁÉÍÓÚÀÈÌÒÙÄËÏÖÜÂÊÎÔÛáéíóúàèìòùäëïöüâêîôû';
  CHARS_SINACENTO = 'AEIOUAEIOUAEIOUAEIOUaeiouaeiouaeiouaeiou';
begin
  Edit2.Text := TranslateChars(Edit1.Text, CHARS_ACENTUADOS, CHARS_SINACENTO);
end;