This is the 1953rd most frequent German word.
englischen
"Englischen" is the declined form of "englisch," meaning "English" in reference to the language or something from England.
Here, 'englischen' is used as an adjective modifying 'Sprache', indicating the language being referred to.
Ich lese gerade ein Buch in der englischen Sprache.
I am currently reading a book in the English language.
In this sentence, 'englischen' is an adjective modifying 'Königin', the queen being referenced, and is in dative case reflecting the grammatical structure.
Der englischen Königin wird Respekt gezollt.
Respect is shown to the English queen.
Here, 'englischen' modifies 'Literatur', describing the topic of discussion, and shows declension according to the compound direct object.