What if we want a word/words that cannot be found in the dictionary (either Quenya or Sindarin), what do we do?
As we said, both Quenya and Sindarin are derived from the same common language. So if we know a word in one language and we want the same word in the other, we consult the other language, or just the appropriate etymological root! These are the ways we follow: Borrowing a word from one language to another: For example, the word for “ring” in Quenya is corma, derived from Common Elvish *corma.. we don’t know the Sindarin form, but after the example of Quenya parma and its Sindarin equivalent parf from Common Elvish *parma, we know that *corma would derive Sindarin *corf. On the other hand, we know that “frog” in Sindarin is cabor, but we dont know the Quenya equivalent. Our understanding of Sindarin evolution shows that cabor derived from Common Elvish *capro… this would derive Quenya *carpo or *capar. Deriving words by affixes: The word for “dynasty” was needed and someone invented the word *hilyale from the verb hilya- “follow, succeed” and the ending -le which forms verbs to nouns
