lesson 26 nouns, and inter-lesson links

docs/howtostudykorean/unit-1/09-conjugate-이다.md

@@ -1260,7 +1260,7 @@ Example:
 
 <Details>
 
-One of the usages of 되다 is to make a verb change to the passive voice. This is introduced in [Lesson 14](https://www.howtostudykorean.com/unit1/unit-1-lessons-9-16/lesson-14-korean-passive-verbs/). For example:
+One of the usages of 되다 is to make a verb change to the passive voice. This is introduced in [Lesson 14](./14-passive.md). For example:
 
 - <TTS class="md">점심이 학교에 준비되었어요</TTS> = <span class="md spoiler">The lunch was provided by the school</span>