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)))))) (. ?)))
The English native speakers are very easily determined.
( ( The ( English ( native speakers ) ) ) ( ( are ( very ( easily determined ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ English) (JJ native) (NNS speakers)) (VP (VBP are) (ADJP (RB very) (RB easily) (VBN determined))) (. .)))