I really don’t like the term ‘accent reduction’. We all have accents. There’s no such thing as reducing an accent to a neutral sound. An American or Canadian accent is still an accent and considered foreign to a Brit or an Aussie.
What really goes on is, you learn how the general majority of the nation uses sound.
If you speak French from Montreal, Canada, and go to Paris, France, you, too, could benefit from ‘accent reduction’. The accent and some vocabulary are different.
If you’re an American, fluent in Russian and living in Russia, you would most likely use American rules for sound, which could make many Russians question what you’re saying.
But back to the USA! It’s all about being better understood. How you produce sounds in your own language or accent can be extremely different to how the American speaks. Vowels and consonants can be hugely different between nations.
SPAIN: A Spaniard saying ‘sun’ might be perceived as saying ‘shun’ to the American. The Spanish S is not exactly like an English language SH sound, but it’s close enough to be confusing.
CHINA: A Chinese person saying ‘little’, might be perceived as saying ‘liddoo’, since the L at the end of words is not used in Chinese languages. Physically, these sounds are vastly different.
*Note: some Americans and Brits do the same thing with the Final L.
INDIA: An Indian saying ‘pay’ might be perceived as saying ‘bay’, because the difference between the Indian and the English language P sound is a tiny puff of air which creates a distinct P.
So, accent reduction is simply about learning new rules, so you can be understood.
And we all know how important communication is. Ask gazillionaire (not a word. I know!) and business magnate, Warren Buffet; “By investing in yourself, like honing your communication skills, you will become worth 50 percent more than you are now.”