Is 晚 a verb or an adjective in the sentence 我 晚了一 个半小? In the sentence below the is word 晚 a verb or an adjective? In the Pleco and other dictionaries says that it is an adjective but I have not seen an adjective with 了 and a duration in any grammar book. Is there a 莱 before understood but not written? Is this a frequently used sentence or better 迟到一个半小时. Here there is no problem since 到 is a verb.

她叫我 十一 以前 到家， 但是我 晚了一个半小?
晚 in "我晚了一个半小时" is an adjective. 

"我(是)晚了一个半小时" = "I (am) late for one and half hour"

The verb 'be' (是) is omitted in Chinese

The verb 'be' cannot be omitted in English. "I was late for one and half hour" cannot be reduced to "I late for one and half hour". 

In "我去晚了一个半小时", '去' is a verb and '晚' is an adverb