Advocate is a synonym of Recommend. Recommend is a synonym of Urge. Urge is related to Motive. Motive is related to Underlying. 
Communication is related to Sign. Sign is related to Written. Written is the opposite of Verbal. 
Advocate <--Synonym--> Recommend <--Synonym--> Urge <--RelatedTo--> Motive <--RelatedTo--> Underlying 
Communication <--RelatedTo--> Sign <--RelatedTo--> Written <--Antonym--> Verbal 