In addition to helping you understand the sounds, I want to give you plenty of ways to practice those sounds, as well as a way to understand word stress (and with it, the pitch and rhythm of American English). Below you will find a list of the kinds of exercises available on this site and an explanation of each kind.
Imitation Exercises: These focus on helping you pick up the speech patterns of American English: how words get stressed and which word/syllables get stressed. You will hear a short excerpt of speech three times, then there will be a gap in the video for you to repeat. Think of it not as repeating words, but as repeating a snippet of music or a melody. The more you imitate the way native speakers use word/syllable stress in speech, the better you will be at doing it yourself. The object is not to think of the words you hear and then same them, the object is simply to imitate the speech exactly as you hear it.
On person wrote in to tell me:
See a list of imitation exercises.
Ben Franklin Exercises: These I model off an exercise that Benjamin Franklin did to improve his writing skill, as described in the book Talent is Overrated by Geoff Colvin. Colvin states that Franklin would take an article from a leading publication and take detailed notes on how it was written. He would then put it away to give his mind time to forget the article, then pull out his notes and try to reconstruct the article from the notes he had made for himself. He would then look at the original article and compare it with the one he had written, and see what still needed work.
I think this is great exercise for pronunciation. I have taken videos and typed up the transcript. I suggest you copy the transcript and print it out, if possible. Then watch the video and take notes about what you hear on the transcript. For example, which syllables/words does the speaker stress? Reduce? Which words get linked to other words? How is the 'ed' pronounced in this word? Which word gets the highest pitch in a sentence? Which words/syllables are so reduced you can hardly hear them? How is the 'T' pronounced in that word? Is 'going to' pronounced 'gonna'? Was this vowel pronounced differently then you expected, and if so what was the vowel pronounced? You get the idea!! Come up with your own way to mark all these things and more in your transcript. Give yourself as much detail as possible; you might have to listen to the video several times. Then wait a few days, or however long you need, and practice saying the text, using your notes as your guide. Record yourself, and compare it to the original. If possible, make a video so you can study how you use your own mouth as you speak. These exercises are a lot of work, but allow you to really take command of your pronunciation!!
See a list of Ben Franklin exercises.