Forty in American English

[belly_ttt]

Do AMericans pronounce " forty" as fordi or forti?
Mr= Mider or mister?

[Soup]

Both, actually: for[D]y and for[t]y; mis[t]er, mis[D]er

[belly_ttt]

So when to use which?>

[up4ever]

from my previous knowledge, this highly depends on regional variation of accents in phonolog (pronunciation).


you could have a quick look at the underneath url,
http://www.englishforums.com/English...ggjcd/post.htm
and concern more with the second reply

[belly_ttt]

But American Accent Course (Ann Cook) says: The soft T is pronounced like a d, so why mister here?
Is the same true with doctor?

[Raymott]

Forty is either /fɔrti/ or /fɔ:ti/ (for non-rhotic speakers), or /forɾi/, where ɾ is an alveolar tap similar to [d].
"Mister" is /mɪstə/, /mɪstər/, /mɪsɾə/, / mɪsɾər/
You should say / /fɔ:ti/ and /mɪstə/ unless you are very keen to adopt the American [r] sounds.

[Soup]

Originally Posted by belly_ttt

But American Accent Course (Ann Cook) says: The soft T is pronounced like a d, so why mister here?
Is the same true with doctor?

Yes. Note that <t> occurs phonetically before a [r] and [i:], both of which are voiced and vocalic. In other words, they act like vowels, as syllabic elements:

mis'ter / mis'[dr]
doc'tor / doc'[dr]
for'ty / for'[di:]