how can i read audio file in matlab?

% read in sound file and determine length and period
[signal, Fs, bits_per_sample]=wavread('speech.wav');

L=length(signal); % file length
T=1/Fs;           % sample period
t=[0:L-1]*T;      % time vector in seconds

% define echo and amplitude values
Te=40;           % set echo to 300 ms 
alpha = 0.9;      % scale amplitude of echo
DelaySec = round(Te / 1000); % must be integer
te = round(DelaySec / T); % echo delay as integer (rel. to sample period)

signalplusecho=1:L+te; % declare it as vector before loop
for t = 1:L+te
   if (t<te)  
       signalplusecho(t)=signal(t);
   elseif (t>=L)              
       signalplusecho(t)=signal(t-te);
   else  
       signalplusecho(t)=signal(t) + alpha*signal(t+te);
   end
end

wavwrite(signalplusecho,Fs,8, 'speechwithecho.wav');