It can be hard to initiate a conversation. Sometimes your mind just goes blank or you feel like what is in your mind is not necessary or interesting to anyone except you. At other times you don't really want to share your thoughts because of what listeners might think of them. Also, your thoughts and feelings may feel so raw and personal that you cannot express them with words. For those reasons talking to people can be difficult and talking to God can feel like an overwhelming task.
Sometimes when you try to pray (or worse: someone unexpectedly calls on you to pray), your mind just goes blank or all you can think of is weird stuff. This often happens because whether you realize it or not, you have probably constructed a specific conception of what prayer ought to be. Maybe you have heard certain leaders in your church pray certain words over and over and decided those words need to be included in every prayer. Also, you may have heard people pray with really beautiful, almost poetic words and thought that it would be really great to also pray so magically. However, God is not concerned with the words you use or even really what you're talking to Him about. God is concerned with you talking to Him at all and about everything and anything on your mind. It is really tempting to want to piece together really eloquent, holy-sounding prayers, but God would honestly rather have you talking to Him about even the weird stuff that just seems to swim around in your head.
Talking to God about anything and everything may sound okay when you're alone in your home, but sound like a bad idea whenever you are praying out loud around other people. Again, it is so necessary to remember that you do not need to pray a certain way. Whether you are alone or with a million people, when you pray, you are talking to just God. It is so necessary to remember to just focus on talking to just God. It may feel really weird, but if you withhold or change the words you say to God based on what other people might think, you miss out on communicating with your Father who loves you and can fill every need you share with Him.
At times you are so full of emotion that you don't care what words you use to pray or who is listening, but what you feel is so deeply felt at the moment that you just can't express it in words. In those times don't worry about using words. The Bible tells us that God knows the depths of each person and that if we are God's followers, He is always with us. That means if you have no words because of your intense emotions, then it is enough to just have the desire to be with God. If you want to be with God, He will be with you in those emotions, taking care of you how He knows best.
Quite often beginning to pray (just like beginning a conversation) is the hardest part. If you start praying to God and keep up the conversation with Him all day long, it will feel more natural to talk to Him about anything regardless of who is listening. If you continue your conversation with God all day, it will also feel more natural when you don't have words but just want to sit and be with God. It really doesn't matter what you pray but that you do talk to God and do keep conversing with God about everything.