Somebody who obviously that English was not their first language, but they wrote a book?
( Somebody ( who ( ( obviously ( that ( ( ( ( English ( ( was not ) ( their ( first language ) ) ) ) , ) but ) ( they ( wrote ( a book ) ) ) ) ) ) ? ) ) )
(ROOT (FRAG (RB Somebody) (WP who) (SBAR (ADVP (RB obviously)) (IN that) (S (S (NP (NNP English)) (VP (VBD was) (RB not) (NP (PRP$ their) (JJ first) (NN language)))) (, ,) (CC but) (S (NP (PRP they)) (VP (VBD wrote) (NP (DT a) (NN book)))))) (. ?)))
Someone who is obviously foreign would have English as their first language.
( ( Someone ( who ( is ( obviously foreign ) ) ) ) ( ( would ( have ( English ( as ( their ( first language ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NN Someone)) (SBAR (WHNP (WP who)) (S (VP (VBZ is) (ADJP (RB obviously) (JJ foreign)))))) (VP (MD would) (VP (VB have) (NP (NP (NNP English)) (PP (IN as) (NP (PRP$ their) (JJ first) (NN language)))))) (. .)))