add_lang.sh now checks whether lang is present
add_lang.sh now checks whether lang is present

shashank19gaurav/tatoeba2,shashank19gaurav/tatoeba2,shashank19gaurav/tatoeba2,shashank19gaurav/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2