At the end of the second year, children begin to label their own and others' internal states with words, such as  want,   happy,   mad,   think,  and  pretend. 
( ( At ( ( the end ) ( of ( the ( second year ) ) ) ) ) ( , ( children ( ( begin ( to ( ( ( ( ( ( ( label ( ( ( their own ) and ) ( ( others ' ) ( internal states ) ) ) ) ( with ( ( ( ( words , ) ( such ( as want ) ) ) , ) ( happy ( , mad ) ) ) ) ) , ) think ) , ) and ) pretend ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (NP (DT the) (NN end)) (PP (IN of) (NP (DT the) (JJ second) (NN year))))) (, ,) (NP (NNS children)) (VP (VBP begin) (S (VP (TO to) (VP (VP (VB label) (NP (NP (PRP$ their) (JJ own)) (CC and) (NP (NP (NNS others) (POS ')) (JJ internal) (NNS states))) (PP (IN with) (NP (NP (NP (NNS words)) (, ,) (PP (JJ such) (IN as) (NP (VP (VB want)))) (, ,)) (ADJP (JJ happy) (, ,) (JJ mad))))) (, ,) (VP (VB think)) (, ,) (CC and) (VP (VB pretend)))))) (. .)))
Usually by the end of the second year, children will begin to label their own and other's internal states with words. 
( ( Usually ( by ( ( the end ) ( of ( the ( second year ) ) ) ) ) ) ( , ( ( ( ( children ( will ( begin ( to ( label ( their own ) ) ) ) ) ) and ) ( other ( 's ( ( internal states ) ( with words ) ) ) ) ) . ) ) )
(ROOT (S (PP (ADVP (RB Usually)) (IN by) (NP (NP (DT the) (NN end)) (PP (IN of) (NP (DT the) (JJ second) (NN year))))) (, ,) (S (NP (NNS children)) (VP (MD will) (VP (VB begin) (S (VP (TO to) (VP (VB label) (NP (PRP$ their) (JJ own)))))))) (CC and) (S (NP (JJ other)) (VP (VBZ 's) (NP (NP (JJ internal) (NNS states)) (PP (IN with) (NP (NNS words)))))) (. .)))