Voice is etymologically related to Advocate. Voice is related to Trait. 
Propose is related to Purpose. Purpose is a synonym of Heart. Heart is related to Vital. Vital is a synonym of Critical. 
Advocate <--EtymologicallyRelatedTo-- Voice <--RelatedTo--> Trait 
Propose <--RelatedTo--> Purpose <--Synonym--> Heart <--RelatedTo--> Vital <--Synonym--> Critical 