lesson 26 nouns, and inter-lesson links

docs/howtostudykorean/unit-1/21-why-when-where-who.md

@@ -1223,7 +1223,7 @@ As you know, some additions require the speaker to choose between two possible o
 In later lessons, you will learn other grammatical additions that have a solid ㄴ. For example:
 
 - \~나 ([later in this lesson](#%E1%84%82%E1%85%A1-%E1%84%8B%E1%85%AD))
-- \~는 ([Lesson 26](https://www.howtostudykorean.com/unit-2-lower-intermediate-korean-grammar/unit-2-lessons-26-33/lesson-26/))
+- \~는 ([Lesson 26](../unit-2/26-describing-nouns-with-verbs.md))
 - \~는데 ([Lesson 76](https://www.howtostudykorean.com/upper-intermediate-korean-grammar/unit-4-lessons-76-83/lesson-76/))
 - \~네 ([Lesson 83](https://www.howtostudykorean.com/upper-intermediate-korean-grammar/unit-4-lessons-76-83/lesson-83/))
 - \~나 ([Lesson 109](https://www.howtostudykorean.com/unit-5/lessons-109-116/lesson-109/))
@@ -1234,7 +1234,7 @@ All grammatical additions where a solid ㄴ is attached to a word follow the sam
 - 마음에 드니? <AudioButton src="https://www.howtostudykorean.com/wp-content/uploads/2015/04/Lesson-21-7.mp3" /> = <span class="md spoiler">Do you like it?</span>
 - 어디 사니? <AudioButton src="https://www.howtostudykorean.com/wp-content/uploads/2015/04/Lesson-21-8.mp3" /> = <span class="md spoiler">Where do you live?</span>
 
-_\~니 also affects the ㅎ irregular,_ which is introduced in [Lesson 23](https://www.howtostudykorean.com/unit1/unit-1-lessons-17-25-2/lesson-23/).
+_\~니 also affects the ㅎ irregular,_ which is introduced in [Lesson 23](./23-ㅎ-irregulars-colors.md).
 
 ### \~ㄴ/은가(요)