They can change the tone of people's voice yes.
( They ( ( can ( ( change ( ( the tone ) ( of ( ( people 's ) voice ) ) ) ) yes ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (MD can) (VP (VB change) (NP (NP (DT the) (NN tone)) (PP (IN of) (NP (NP (NNS people) (POS 's)) (NN voice)))) (NP (RB yes)))) (. .)))
They use a computer to change people's tone of voice.
( They ( ( use ( ( a computer ) ( to ( change ( ( ( people 's ) tone ) ( of voice ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBP use) (S (NP (DT a) (NN computer)) (VP (TO to) (VP (VB change) (NP (NP (NP (NNS people) (POS 's)) (NN tone)) (PP (IN of) (NP (NN voice)))))))) (. .)))