Note 3 at Mr 11:14: Notice this verse says that Jesus "answered" this fig tree. The tree had not spoken to Him verbally, but it had communicated that it had figs by the leaves on the tree (see note 1 at Mt 21:19). Not only plants but other things can communicate with us too. Circumstances can tell us that we have failed. Our bodies can tell us that our prayers didn't work, the Lord didn't heal us, etc. We need to follow Jesus' example and answer these things with a positive statement of our faith.

Note 4 at Mr 11:14: Jesus was not only having trees talk to Him (see note 3 at this verse, but He was also talking to them. Jesus also encouraged us to speak to mountains (Mr 11:23) or to whatever our problems might be. What good could it do to talk to a tree or an inanimate object?

God created the heavens and the earth and everything that is in the earth by His words (Heb 11:3). The whole creation was made by and responds to words. Our words, when spoken in faith, release either life or death (Pr 18:21) and will affect people, things, and circumstances. We can release the power that is in faith by our words, as Jesus went on to explain to His disciples (see note 4 at Mr 11:23).