The Spanish lesson that would require knowledge of domain-specific vocabulary that you would also use in an English language arts class is:
a poem written about Sancho Panza, loyal sidekick to the protagonist of the European novel Don Quixote.
This lesson incorporates literary analysis and understanding of character development, which are relevant in both Spanish and English language arts classes. Additionally, discussing themes, literary devices, and character relationships in the context of a well-known literary work connects directly to English language arts vocabulary and concepts.