What is the relationship among Aramaic, Arabic and Hebrew?

I have very little knowledge and a lot of confusion about this topic. Why is Aramaic so similar to modern-day Arabic? Why did Jesus, a Jew, speak Aramaic? When did the Jews start speaking Hebrew?

Please, only scholarly replies. Thanks
Update: Thank you Taivo for your answer. Could you expound on the history of the Arabic language and why modern-day Arabs can understand Aramaic? Your input is invaluable to me.
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