Indeed, the central purpose of language, from its moment of emergence, is  communication, social contact, infiuencing surrounding individuals. 
( Indeed ( , ( ( ( ( ( ( the ( central purpose ) ) ( of language ) ) , ) ( from ( ( its moment ) ( of emergence ) ) ) ) , ) ( ( is ( ( ( ( communication , ) ( social contact ) ) , ) ( infiuencing ( surrounding individuals ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Indeed)) (, ,) (NP (NP (DT the) (JJ central) (NN purpose)) (PP (IN of) (NP (NN language))) (, ,) (PP (IN from) (NP (NP (PRP$ its) (NN moment)) (PP (IN of) (NP (NN emergence))))) (, ,)) (VP (VBZ is) (NP (NP (NP (NN communication)) (, ,) (NP (JJ social) (NN contact)) (, ,)) (VP (VBG infiuencing) (S (VP (VBG surrounding) (NP (NNS individuals))))))) (. .)))
Only two factors form the central purpose of language: communication and social contact.
( ( Only ( two factors ) ) ( ( form ( ( ( ( the ( central purpose ) ) ( of language ) ) : ) ( ( communication and ) ( social contact ) ) ) ) . ) )
(ROOT (S (NP (RB Only) (CD two) (NNS factors)) (VP (VBP form) (NP (NP (NP (DT the) (JJ central) (NN purpose)) (PP (IN of) (NP (NN language)))) (: :) (NP (NP (NN communication)) (CC and) (NP (JJ social) (NN contact))))) (. .)))