why humans having a single tongue

if god gave you another tongue where did you put that tongue in your body and by which tongue you will answer

To talk less and work more and also tongue is not to use for two speach

Since mouth is also single so no place for the second tongue.

Actually, if you look far enough back humans have what some refer to as a 2nd tongue. it's a little tongue that is actually at the base of your big tongue... kinda weird. I'm not talking the thing that hangs in the back of your throat either.. it's at the base of the back of your tongue. Look in the mirror, you should be able to see it.

Yes. I have reason that God made us perfect and beautiful. That is a good reason for me. Simply the best reason.