All languages indicate the relationship between verbs and their arguments by constituent order, case marking and agreement. Case marking has many forms such as nominative-accusative, neutral, ¬ergative-absolutive, quasi-neutral, and tripartite. Ergative-absolutive system or ergative is the case of A or the subject of transitive verbs. Tati, Taleshi and Guilaki languages are from Iranian Caspian languages group. Tati and Taleshi have ergtive system but it is not common in Guilaki. This paper tries to analyze the ergatives’s Sediments in these languages. It is shown that Tati and Taleshi are losing some ergative properties, for example clitics are going from second (wackernagel) position toward verb, agreement between verb with object in gender, number and person is gradually disappearing.
