MATLAB: Say /a/

speech recognition

how can I write a program in matlab to say /a/?

On a PC

    textIn = 'ah';
    ha = actxserver('SAPI.SpVoice');
    invoke(ha,'speak',textIn);

Laura - I think that you want to use audioread first as

 m4AFilename = 'hoi.m4a';
 [y,Fs] = audioread(m4AFilename);

and then write it as a wav file using audiowrite as

 wavFilename = 'hoi.wav';
 audio write(wavFilename,y,Fs);

Try the above and see what happens!

You mean have the computer synthesize speech?

On Windows, this can be done using .NET. There happens to be an example of this in a blog post on .NET in MATLAB.
On a Mac, use the "say" system command:

system('say "Hello, World!"')

On Linux, techniques may vary from distro to distro. Links like this and this may be helpful, and then you can use the system command like in the Mac case.