The controller only heard something unintelligible; he did not hear the specific words we have some planes.
( ( ( ( ( The controller ) ( only ( heard ( something unintelligible ) ) ) ) ; ) ( he ( ( did not ) ( hear ( ( the ( specific words ) ) ( we ( have ( some planes ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT The) (NN controller)) (ADVP (RB only)) (VP (VBD heard) (NP (NN something) (NN unintelligible)))) (: ;) (S (NP (PRP he)) (VP (VBD did) (RB not) (VP (VB hear) (NP (NP (DT the) (JJ specific) (NNS words)) (SBAR (S (NP (PRP we)) (VP (VBP have) (NP (DT some) (NNS planes))))))))) (. .)))
The words were garbled and the controller couldn't understand them.
( ( ( ( ( The words ) ( were garbled ) ) and ) ( ( the controller ) ( ( could n't ) ( understand them ) ) ) ) . )
(ROOT (S (S (NP (DT The) (NNS words)) (VP (VBD were) (VP (VBN garbled)))) (CC and) (S (NP (DT the) (NN controller)) (VP (MD could) (RB n't) (VP (VB understand) (NP (PRP them))))) (. .)))