Forms title bar buttons issues

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C#

.NET

WinForms

C#4.0

.NET4

http://stackoverflow.com/questions/12329421/is-there-a-way-to-check-when-mouse-is-above-standard-window-control-buttons-clo[^]

This code is not mine. I went through the above link and I had made some alteration according for my requirement. I'm trying to code mouse enter & mouse leave event for minimize & close button of form in c#?

SpeechSynthesizer reader;
internal const int WM_NCMOUSEMOVE = 0x00A0;

protected override void WndProc(ref Message m)
{
    if (m.Msg == WM_NCMOUSEMOVE)
    {
        //Mouse over on Minimize button
        if ((int)m.WParam == 0x8)
        {
            reader = new SpeechSynthesizer();
            reader.SpeakAsync("Minimize button");
        }

        //Mouse over on Maximize button
        if ((int)m.WParam == 0x9)
        {
            reader = new SpeechSynthesizer();
            reader.SpeakAsync("Maximize button");
        }

        //Mouse over on Close button
        if ((int)m.WParam == 0x14)
        {
            reader = new SpeechSynthesizer();
            reader.SpeakAsync("Close button");
        }
    }

    base.WndProc(ref m);
}

My Questions:
1. How can I use reader.SpeakAsync (Asynchronous) method without repeating. Since if I use reader.speak (Synchronous) that will wait process until it finish reading text.
2. Also I need to implement mouse leave event. Because if mouse leaves the button, I do want to call reader.Dispose() method. Are there any way to implement mouse leave events?
Please help.