impregnable Non-English speakers have been known to think this means inconceivable.
( ( impregnable ( Non-English speakers ) ) ( ( have ( been ( known ( to ( think ( ( this means ) inconceivable ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ impregnable) (JJ Non-English) (NNS speakers)) (VP (VBP have) (VP (VBN been) (VP (VBN known) (S (VP (TO to) (VP (VB think) (S (NP (DT this) (NNS means)) (ADJP (JJ inconceivable))))))))) (. .)))
Some non-English speakers have misunderstood what it means.
( ( Some ( non-English speakers ) ) ( ( have ( misunderstood ( what ( it means ) ) ) ) . ) )
(ROOT (S (NP (DT Some) (JJ non-English) (NNS speakers)) (VP (VBP have) (VP (VBN misunderstood) (SBAR (WHNP (WP what)) (S (NP (PRP it)) (VP (VBZ means)))))) (. .)))