A lot of my students ask me: “I studied the British accent in my country. How is the American accent different?”
Some of the major differences between the American and British accents are the pronunciation of several vowel sounds, and the pronunciation of the letters “r” and “t.” The pronunciation of the vowels /ɔ/ as in “all” “awful,” and /æ/ as in “last” and “class” are the most noticeable vowel differences.
Also, Americans pronounce all of the “r”s, whereas in British English the final “r” and an “r” before another consonant are often silent. For example, the words “for” sounds like “foe” in British, and the word “morning” sounds like “moaning.”
The letter “t” in the words “better” and “water” is pronounced differently in the two accents. The “t” between two vowels usually sounds similar to a “d” in American English. Thus, “latter” and “ladder” sound exactly the same. Also, “atom” and “Adam” are pronounced the same in American English. (The second vowel in each of these words is reduced. That’s why the “o” of atom and the second “a” of Adam sound exactly the same.)
Several verbs in the past tense are spelled with “ed” in American English and “t” in British English and are thus pronounced differently. For example Americans say “learned” and “burned” whereas British speakers say “learnt” and “burnt.”