It's Yo sé because sé is the conjugate verb for yo so it would be:
Yo sé más del lenguaje hindi, pero no tengo con quien practicar.
Okay so the ones that you do have answered are correct with the exception of number 13 which should be, 'Los alumnos'. Number 8, the beards, would be 'Las barbas.' Number 14, the television, would be 'La television.' Number 15, a few decisions, would be 'Unas pocas decisiones.' And lastly, Number 16, the jacket, would be 'La chaqueta.' I hope this helped!
I'm pretty sure your answer should be ¿Puedo dejarle un mensaje? . Hope this helps! =^-^=
