How did bilingual Sumerian and Babylonian texts help scholars decipher Sumerian?

Bilingual texts were instrumental in deciphering the Sumerian language because they provided a direct bridge between the unknown Sumerian and the already understood Akkadian (Babylonian) language.12

After Sumerian ceased to be a spoken language around 2000 BCE, it persisted as a prestigious cult idiom within Babylonian religion. To assist priests in learning this "dead" language, Babylonian scribes compiled extensive educational materials, including:12

• Lexicographical texts: These served as dictionaries, where individual Sumerian lexical entries were translated into Akkadian and often annotated with phonetic signs.3
• Grammatical treatises: Scribes created "paradigms" that translated Sumerian pronouns, verb forms, and other grammatical structures into Akkadian, despite the fundamental differences between the two languages.3
• Bilingual literary texts: Many religious and literary compositions were provided with line-by-line translations into Babylonian.13

These resources, preserved by the ancient schools, allowed modern scholars to penetrate the structure of unilingual Sumerian texts, eventually enabling the successful reconstruction of Sumerian grammar and vocabulary.132