There has been no teaching of past tense; therefore, "does not talk" should be correct, even though it is not grammatically correct in English.
With examples like this, we can start to understand that the present tense in Portuguese, which we have learned, does not always translate to a simple present tense in English. This is an important grammatical subtlety.
I don't have a difficulty with the grammatical subtleties, but when they have not taught on it, then it should not be required as a correct answer. Once they introduce past tense, then it can be part of the correct answers.
You don't need to be taught past tense in Portuguese to know the past tense in English. Here you learn that the present tense in Portuguese is used to express things we would use past tense for in English. It would be even more confusing to include this in a lesson on the past tense, since this verb is in present tense. As someone suggested, maybe it could be moved into a lesson on situations where tenses do not match. In any case, gramatically incorrect translations should never be accepted.
Duo accepted "He doesn't talk since yesterday" on 06-Nov-2015. BTW: it is not incorrect grammar in English, even if it may seem odd to some native speakers.
Duo accepted "He doesn't talk since yesterday" on 06-Nov-2015
Not accepted anymore in July-29-2018 (as expected):
- "He does not talk since yesterday"
- "He does not speak since yesterday"
Duolingo corrected answer suggestion:
"He has not talked since yesterday."
30 Dec 2018, I confirm that: "He does not talk since yesterday" is still not accepted. However Delvi, Duo did teach the past tense 2 lessons ago (see Pret Perf). In this sentence, I believe the answer should be the present continuous: "He has not been talking since yesterday".
Of course it's grammatically wrong. An action started in the past and still ongoing at the time of speaking requires have + past participle (present perfect) or have been + -ing (present perfect continuous).
It is very much incorrect grammar. We can put aside the negative: 'not'. What you are saying is that 'he does talk since yesterday' is correct. The closest you can get to this being acceptable is the sentence:
He does talk - since yesterday.
...and even then, it would have to come as a rebuttal to someone who said something such as 'he still doesn't talk'. Other than that, the sentence must be modified for it to make sense. There are many slight changes such as:
He hasn't talked since yesterday. He didn't talk yesterday. He doesn't talk, so of course he didn't talk yesterday.
Be careful with statements such as the one you made as some people could be steered in the wrong direction.
This is exactly the way it should be translated, but is inconsistent with similar exercises.
I had a problem with that also, but we would not use the present tense in English and say "since yesterday." So, when one stops to think about it, it needs the past tense of the verb. I agree that it should not be in this lesson because past tense has not been introduced at all. The lesson is on present tense verbs.
I think their logic for including this here is that the lesson is about present tense verbs in Portuguese (not English), and this is a fairly simple sentence that uses a present tense verb in Portuguese. It may be a bit early in the lesson sequence to include an example where the verb tenses don't line up nicely in both languages, but it would also be wrong to put this is in a lesson on the past tense because you don't use the past tense in Portuguese in this context. Maybe it would fit better in a lesson that's not about about verb tenses at all but focuses instead on problem words for English-speaking learners, like "desde".
If you think your answer is right, report it. That is better than posting it here in the discussion.
The "present perfect tense" used with the adverb "since" describes an action that started in the past (yesterday) and continues to the moment of speaking.
He has not spoken since yesterday.
I find this a terrible exercise. And reported it after trying a few solutions. Yes did not speak should be right as well.
"You did not speak" focuses on a past completed action while "You have not spoken" focuses on a period of time from the past to the present moment.
It concerns an ongoing, current fact, that is presented in present perfect (in English). It's not an action that happened in the simple past - which "falou" would be used for.
Why is it wrong to say "he didn't talk since yesterday"? Isn't this the meaning of the sentence?
"Since yesterday" is an ongoing thing. It includes the current time and has the potential for continuation. It's not a specific action in the past. "Didn't talk" is used when referring to something that has been and gone in the past (not an ongoing thing started in the past).
"He didn't talk yesterday" and "he hasn't spoken since yesterday" are the two most simple options with this one.
I noticed another exercise during this lesson (Preposition 3 or 4) that said: "Ela não bebeu cerveja desde ontem". This says "Ele não fala desde ontem". Why is there a difference in tense? Is the focus in the first sentence on the act of drinking beer, and that she has not done that since yesterday, and in the second one that he doesn't speak now, and has not done so since yesterday?