How to Pronounce Different Words in English

I want to warn all of you about variations in pronunciation in English. You see how the A is pronounced differently each time. I mean even like the letter E, we have a letter, letter,. letter, letter,letter, E, those are all E's. Then you have, you know, heard as an E, but then you can get the E sound with bird or word or squirrel and so on. So if you are aware of these changes, you may not make so many mistakes. The hard part is that I can warn you, scare you, prepare you, and what happens.