After a looooong time, here is a new post!
One of my students asked why the following question was marked wrong by the textbook's online component,
Los tres idiomas que se hablan en Bolivia son _______, ________ y ________.
His answer was,
Los tres idiomas que se hablan en Bolivia son español, aimará y quechua.
The names of the languages are correct, but the grammar, according to the online workbook, i wrong. Why?
This is my answer.
Here the definite article is needed because this an identification of nouns; in this case languages.
It is the equivalent of this in English,
The thee languages spoken in Bolivia are the Spanish language, the aimará language, and the quechua language.
The key is "Los" at the beginning of the sentence. This means that those are THE three languages and there are no more than three. If instead of "Los tres idiomas" we had "Tres idiomas...." then we would be able to just name the languages without the article. It would also imply that there are more languages that Bolivians speak. So, consider this:
Los tres idiomas que se hablan en Bolivia son el español, el aimará y el quechua.
Tres idiomas que se hablan en Bolivia son español, aimará y quechua.
The two sentences mean basically the same when you translate them into English. However, from a grammatical point of view, they are different. The first one means that only three language are spoken in Bolivia, while the second one means that three of the languages are Spanish, Aimará, and Quechua, and there are more than three. The reason why el, la, los, las (the) are definite articles is that they make the nouns more important and not part of a simple list, but the list of something.
I hope this helps.