In British English we don't use the past simple tense to talk about an action in the recent past that has a present result. We use the present perfect. 'I have not talked to you yet' is present perfect and means 'up until this present moment'. In American English it is possible to use the past simple to mean the same thing. 'I didn't talk to you yet.' The same is also true with the use of 'just' and 'already'. In American English you can say 'I just had lunch'. In British English we say 'I have just had lunch.' In American English you can say' I already saw that film'. In British English we say 'I have already seen that film.' In conversation both are forms are acceptable. But in British English Exams and English language tests using the past simple in this way would be considered incorrect.

I didn't talk to you yet.=一般过去时，强调是过去的动作 I haven't talked to you yet=现在完成时，过去的某一时间开始并持续到现在的动作，yet在这个句子里译成“还hai”。我还没和你谈过呢（表示将来可能会和“你”谈哦）

The meanings of these two sentences are the same.But the former one is more used in American English(I didn't talk to ya yet),And the second one is frequently used in British English.都是一个意思，只不过前一个是美式英语，美国人有时候也会说第二种(I haven't talked to you yet)，第二种一般是非美国人说的，都是完成时。