You are right and the English translation, although I do hear my two American sons in-law use it sometimes, is informal and would be marked wrong in an IELTS, a TOEFL or a SAT test, for example. You are taught to use the simple past with specific time past events, and the perfect with "yet", "already", "just", which indicate that the past event is somehow related to a present: "They say that the parcel has already arrived. It arrived yesterday". "I had just started cooking when the telephone rang." "She asked me if I had had dinner yet." "I had just got into the bathtub when the postman arrived!" "The children arrived from school at four on the dot."
Precisely. "Did you already open the letters?" is bad grammar because the question is attempting to combine two incompatible tenses. "Did you open the letters?" is otherwise grammatically correct. But we must translate "Ya", here, and therefore English grammar demands the present perfect tense: "Have you already opened the letters?"
It may be that "Did you already...." is considered to be bad grammar or at least not common in British English. However, it's acceptable in American English.
According to Practical English Usage by Michael Swan page 558, "In British English, perfect tenses are common with already and yet; Americans often use past tenses."
That said, I think that "Have you already..." should be accepted for this sentence even though the Spanish sentence is the preterite and not present perfect. British people shouldn't be forced to use grammar that doesn't feel natural to them.
You are confusing a grammatical nicety with bad syntax, MayteStiles. Similarly jopopojo is splitting hairs, as well as incorrect, when he opines that "Did you already open the letters?" contains bad grammar. "Already" is not the only translation of "ya." "Ya" can also be translated as "now" or "yet." In Spanish sentences like this one, I always choose the "yet" interpretation: Did you open the letter yet?
Different regions use different colloquialisms. The reason why "have you opened" doesn't work as a translation is that this concatenation is English Perfect Tense, and "abriste" is Spanish Imperfect Tense. Unless there are compelling idiomatic reasons, there is no reason to switch tenses when translating.
The compelling reason is that there are regional differences in what is considered common, natural, and correct.
Present perfect would be used in Spain and England in this case. However, preterite would be acceptable in the United States and required in some parts of South America such as Argentina.
There aren't a huge number of grammatical differences between various regions, but this is one of them.
The drop-down list of hints is not context sensitive. Words in both English and Spanish mean many different things. Cartas doesn't mean"card" in this context for this sentence. However, it can't be removed from the list because it sometimes does mean "card" in other sentences.
Greeting card = tarjeta
Playing card = carta
There's no way to open a single playing card. I suppose you could open a deck/pack of playing cards if it were wrapped in plastic or in a box. However, that would "baraja de cartas" or "mazo de cartas."
When you state that "Duo is using the simple past tense here in a wrong way," are you saying that Spanish doesn't use its simple past tense (aka Preterite) to convey the message "Did you already open the letters?" That is, are you saying that "¿Ya abriste las cartas?" should be translated as something else? From other posts on this page, I gather that the adverb "ya" causes a lot of consternation when it is translated as "already." Would translating "ya" as "yet" help? ("Did you open the letters yet?") Another translation of "ya" is "now." If you choose to use the English adverb "now," the sentence has to be recast in either English Present Perfect Tense OR English Present Continuous Tense: "Are you opening the letters now?" The reason why is because the past tense meaning of "did you open" conflicts with the present tense meaning of "now."
As I write this, I have more insight into why a native Spanish speaker doesn't like the "Abriste las cartas ya?" I answered my own questions. The reason why native Spanish speakers don't like this sentence is because "abriste" is past tense and "ya" can mean either "already," "yet," or "now." In conclusion, I understand now your contention that Spanish Present Perfect Tense should be used. For this reason, I am downvoting this sentence because the best translation of "Did you already open the letters?" is "Ya has/ha abierto las cartas?" (Have you opened the letters yet?/Have you opened the letters now?)
From A New Reference Guide to Modern Spanish page 228, "The rules governing the perfect tense in Central Spain also apply, with some slight differences in Bolivia and Peru, and to one or two neighboring areas. In most of the rest of Latin America, all completed actions tend to be expressed in informal language by the preterite tense. This solution is so favoured in informal styles in some regions that the perfect tense is rarely heard... The perfect tense seems to be least popular in everyday speech in Buenos Aires city and is said to sound bookish there. In Mexico, and many other places, the perfect tense expresses completed actions."
For British speakers, using words like already or yet with the simple past tense isn't common. As a result, it may not feel right or natural to them to have to translate the Latin American "¿Ya abriste...? to "Did you already..."
OK. That's a "tarjeta," and not a "carta." The use of "carta" to mean "card" applies to playing cards rather than cards you might send to someone. There's also an auto insurance document colloquially called a "green card" or "carta verde," but that's the only other use of "carta" as "card" I can find.