which lang i shuld use to convert elec. sgnls to voice sgnls,also which device

i designed a 4wheeler small robo car,which runs with a servo motor.
with assembly language installed in it,the car automatically runs,and turns left and right such that it doesnt crosses the LINE.
What i need is , when the car turns left,it must generate a voice signal saying "turning left" , when it turns right,it must generate voice signal saying " turning right", for generating that voice signal,which language(like c,java,assembly lang) should i use,and what kind of memory should i use.
Thanks in advance.

probably a more general response than you'd hope, but check out Roman Black's BTc for a software solution or perhaps this device for a hardware solution.