I can say to you that, in Brasil, it's possible to realise different sounds for the "d" and for the "t". - the "d" combined with "a", "e" "o" and "u" sounds like the "d' of these english words: "dark", "desert", "domestic" and "do". - the "d" combined with "i" is mostly pronounced as the english "j" like in the word "jeep" (but in some parts of Brasil the "d" with "i" is pronounce like the "d" of the english word "did"). The two forms are correct but i think that is better to choose the most used sound. - the "t" combined with "a", "e" "o" and "u" sounds like the "t' of these english words: "talent", "tell", "tall" and "tooth". - the "t" combined with "i" is mostly pronounced as the english "ch" like in the word "cheap" (but in some parts of Brasil the "t" with "i" is pronounce like the "t" of the english word "teen").The two forms are correct but i think that is better to choose the most used sound.

Luciano is right about the combinations with 'd' and 't'. Also, they are pronounced differently in different regions. Most people want to learn the pronunciation of Rio, São Paulo and Belo Horizonte. I found that in the South East of Brazil, they mostly go like this: D - Before all letters except 'i', it is a hard 'd' like 'dog'. Before 'i', it is a soft d, like 'j' in English. So 'diga' sounds like 'jeega'. ALSO, this happens to 'd' before a final 'e' in any word. Thus: balde (bucket) sounds like 'bawl-jee' rude (rude) sounds like 'hoo-jee' and cidade (city) sounds like 'si-da-jee' T - Before all letters except 'i', it is a hard 't' like 'talk'. Before 'i', it is a soft 't', like 'ch' in English. So 'tive' sounds like 'chee-vee'. ALSO, this happens to 't' before a final 'e' in any word. Thus: sente (you feel) sounds like 'sen-chee' bate (you hit) sounds like 'ba-chee' and independente (independent) sounds like 'in-de-pen-den-chee Finally R. This one changes the most. At the beginning of a word, it is usually like a strong 'h'. rosa (pink) sounds like 'ho-za'. After a consonant and in the middle of a word, it is trilled like spanish or italian 'r' traigo (I bring) sounds like 'trry-go'. A double 'r' (rr) in the middle of 2 vowels is a very strong, grating 'h', like spanish 'j' or arabic 'h' corra (run!) sounds like 'cor-Ha' and empurra (push) sounds like 'em-poo-Ha' Lastly the final 'r' changes a lot depending on area. In some areas it is very slight and almost inaudible, like the preceding vowel is long. In other areas it is like the initial 'r', a soft 'h' sound. I've also heard it like the strong double 'r' sound and also like american english 'r' which is very rounded. So cantor (singer) can be like 'cantow', 'cantoh', 'cantoH' or 'cantor' Phew!

See this site (http://www.easyportuguese.com/). In it, you can listen the pronuciation together. I hope it helps you.

O "R" para você em português é difícil e o "R" para nós em inglês é difícil. O "T" e o "D" você vai perceber que existe muita diferença no som. The portuguese letter "R" is hard to you and the english letter "R" is hard to us. You will know the difference in pronunciation between sounds like "T" and "D". Right?