difference between scream, screech, shout

scream - [intransitive, transitive](чарлах, орь дуу тавих) санамсаргүй айн дуу хадуулах
1 to give a loud, high cry, because you are hurt, frightened, excited, etc.
     --- He covered her mouth to stop her from screaming.
2 to shout something in a loud, high voice because of fear, anger, etc.
     --- “Help!” she screamed.
screech - [intransitive, transitive] (бархирах, хүчтэй дуугарах, хашгирах) энэ дуугаар ямар нэгэн юм хэлэх
to make a loud, high, unpleasant sound; to say something using this sound
   --- Monkeys were screeching in the trees.
   --- He screeched with pain.
shout - [intransitive, transitive] (хашгичих, орилох) ууртайгаар хэн нэг рүү орилох
to say something in a loud voice; to speak loudly/angrily to someone
    --- Stop shouting and listen!

difference between scream and screech

• Hi. Scream is used to describe loud cry of a person as a rule. She screamed with a horror when saw what she did. 
  Screech is likely to relate to any mechanisms. The car' brakes screeched terribly from huge strain but that saved driver's life. 

difference between scream and shout

• The tone in your voice I would believe. I would think shouting is something you do to gain someones attention who previously was unaware(дуулаагүй, тоожиргүй) that you needed their attention,and screaming is something I think you do unintentionally(санамсаргүйгээр) upon being startled(айх, үргэх) of scared.