When is the definite article used before a language name?

Question

When is the definite article supposed to be used in front of a language name? For example, Deutsch vs. das Deutsche, Englisch vs. das Englisch.

As an English speaker, the definite article is not used before language names under any circumstances, so my intuition offers no help in this matter.

Here is a random example:

...in den beiden Luxemburger Schulsprachen Deutsch und Französisch, aber auch in Englisch an der Studie teilnehmen konnten.

With the definite article:

Bei aller Liebe für das Englisch kann es einem deutschen Aktionär nicht zugemutet werden, die meist komplizierten Sachverhalte in Englisch nachzuvollziehen.

Answer 1

As an English speaker, the definite article is not used before language names under any circumstances, so my intuition offers no help in this matter.

Are you quite sure? What about something like "The English spoken in England is quite different from ..." or "The American English of the 17th and 18th centuries ...? I don't think it's all that different from German, actually: in most cases you'll use the language name without an article, but if you are referring to a particular variant (say, "the Queen's English") you will use it.

In your second example the writer talks about a particular variety, the English spoken in Singapur. That said, I share chirlus concern, the sentence is perhaps not the best example.