[dec]

Hola,

No diré que sea perfecto, pero, igual puede darte alguna idea:

Código Delphi [-]
unit Project.SampleForm;

interface

uses
  Vcl.Forms, Vcl.ExtCtrls, System.Classes,
  Vcl.Controls, Vcl.StdCtrls;

type
  TSampleForm = class(TForm)
    TypeEdit: TEdit;
    TypeEditTimer: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure TypeEditTimerTimer(Sender: TObject);
  private
    FCurrentCharNum : integer;
    FSavedTypeEditText : string;
  end;

var
  SampleForm: TSampleForm;

implementation

{$R *.dfm}

procedure TSampleForm.FormCreate(Sender: TObject);
begin
  FCurrentCharNum := 0;
  TypeEditTimer.Interval := 50;
  TypeEditTimer.Enabled := true;
  FSavedTypeEditText := TypeEdit.Text;
end;

procedure TSampleForm.TypeEditTimerTimer(Sender: TObject);
begin
  if TypeEdit.Text = FSavedTypeEditText then
    FCurrentCharNum := 0
  else
    Inc( FCurrentCharNum );

  TypeEdit.Text := Copy( FSavedTypeEditText, 1, FCurrentCharNum );
  TypeEdit.SelStart := Length( TypeEdit.Text );
end;

end.