 Yes, I understand.
( Yes ( , ( I ( understand . ) ) ) )
(ROOT (S (INTJ (UH Yes)) (, ,) (NP (PRP I)) (VP (VBP understand)) (. .)))
I understand what you are saying about that.
( I ( ( understand ( what ( you ( are ( saying ( about that ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP understand) (SBAR (WHNP (WP what)) (S (NP (PRP you)) (VP (VBP are) (VP (VBG saying) (PP (IN about) (NP (DT that)))))))) (. .)))