Should which also be accepted?
I wrote two books, neither of them wrote back to me.
I get the point, but that is a quirk of US English where "to" is omitted e.g. "I wrote to her", being reduced to "I wrote her", such an ambiguity does not exist in British and most other dialects of English where "to" would be used.
What about 'CUAL libro escribiste' ?
You can't use 'cual' directly in front of a noun. '¿Cual es el libro que escribiste?' is the closest thing that comes to mind.
"Cuál" (with an accent when interrogative particle) is a pronoun. It replaces a noun and, thus, does not go along it. "Cuál" may mean "Which one"
Are you implying that "cual" with no accent is acceptable in LaAm Spanish, i.Quilez?
Cual without an accent is acceptable when it's not an interrogative pronoun, but that is true for any version of Spanish.
A question i would like to ask all the people who complain about the wording of the phrases in English ;.)