diff --git a/ext/js/language/ko/korean-transforms.js b/ext/js/language/ko/korean-transforms.js
index d51d0209e..ff4ac6a02 100644
--- a/ext/js/language/ko/korean-transforms.js
+++ b/ext/js/language/ko/korean-transforms.js
@@ -3444,18 +3444,18 @@ export const koreanTransforms = {
                 suffixInflection('ㅇㅓㄹㅏ', '', [], ['p', 'f']),
             ],
         },
-        '-아/아서': {
-            name: '-아/아서',
+        '-아/어서': {
+            name: '-아/어서',
             rules: [
                 suffixInflection('ㅏㅅㅓ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅓㅅㅓ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅏㅅㅓ', 'ㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅓㅅㅓ', 'ㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅓㅅㅓ', 'ㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅏㅅㅓ', 'ㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅓㅅㅓ', 'ㅓㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅅㅓ', 'ㄷㅏ', [], ['v', 'adj', 'ida']),
+                suffixInflection('ㅅㅓ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅕㅅㅓ', 'ㅣㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅕㅅㅓ', 'ㅇㅣㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅕㅅㅓ', 'ㅇㅣㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅎㅐㅅㅓ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅎㅏㅇㅕㅅㅓ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅗㅏㅅㅓ', 'ㅂㄷㅏ', [], ['v', 'adj']),
@@ -3485,12 +3485,12 @@ export const koreanTransforms = {
                 suffixInflection('ㅏㅇㅑ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅓㅇㅑ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅏㅇㅑ', 'ㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅓㅇㅑ', 'ㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅓㅇㅑ', 'ㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅏㅇㅑ', 'ㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅓㅇㅑ', 'ㅓㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅑ', 'ㄷㅏ', [], ['v', 'adj', 'ida']),
+                suffixInflection('ㅇㅑ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅕㅇㅑ', 'ㅣㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅕㅇㅑ', 'ㅇㅣㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅕㅇㅑ', 'ㅇㅣㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅎㅐㅇㅑ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅎㅏㅇㅕㅇㅑ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅗㅏㅇㅑ', 'ㅂㄷㅏ', [], ['v', 'adj']),
@@ -3520,12 +3520,12 @@ export const koreanTransforms = {
                 suffixInflection('ㅏㅇㅑㄱㅔㅆ', 'ㄷㅏ', ['f'], ['v', 'adj']),
                 suffixInflection('ㅓㅇㅑㄱㅔㅆ', 'ㄷㅏ', ['f'], ['v', 'adj']),
                 suffixInflection('ㅇㅏㅇㅑㄱㅔㅆ', 'ㄷㅏ', ['f'], ['v', 'adj']),
-                suffixInflection('ㅇㅓㅇㅑㄱㅔㅆ', 'ㄷㅏ', ['f'], ['v', 'adj']),
+                suffixInflection('ㅇㅓㅇㅑㄱㅔㅆ', 'ㄷㅏ', ['f'], ['v', 'adj', 'ida']),
                 suffixInflection('ㅏㅇㅑㄱㅔㅆ', 'ㅏㄷㅏ', ['f'], ['v', 'adj']),
                 suffixInflection('ㅓㅇㅑㄱㅔㅆ', 'ㅓㄷㅏ', ['f'], ['v', 'adj']),
-                suffixInflection('ㅇㅑㄱㅔㅆ', 'ㄷㅏ', ['f'], ['v', 'adj', 'ida']),
+                suffixInflection('ㅇㅑㄱㅔㅆ', 'ㄷㅏ', ['f'], ['v', 'adj']),
                 suffixInflection('ㅕㅇㅑㄱㅔㅆ', 'ㅣㄷㅏ', ['f'], ['v', 'adj']),
-                suffixInflection('ㅇㅕㅇㅑㄱㅔㅆ', 'ㅇㅣㄷㅏ', ['f'], ['v', 'adj']),
+                suffixInflection('ㅇㅕㅇㅑㄱㅔㅆ', 'ㅇㅣㄷㅏ', ['f'], ['v', 'adj', 'ida']),
                 suffixInflection('ㅎㅐㅇㅑㄱㅔㅆ', 'ㅎㅏㄷㅏ', ['f'], ['v', 'adj']),
                 suffixInflection('ㅎㅏㅇㅕㅇㅑㄱㅔㅆ', 'ㅎㅏㄷㅏ', ['f'], ['v', 'adj']),
                 suffixInflection('ㅇㅗㅏㅇㅑㄱㅔㅆ', 'ㅂㄷㅏ', ['f'], ['v', 'adj']),
@@ -3554,12 +3554,12 @@ export const koreanTransforms = {
                 suffixInflection('ㅏㅇㅑㅁㅏㄴ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅓㅇㅑㅁㅏㄴ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅏㅇㅑㅁㅏㄴ', 'ㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅓㅇㅑㅁㅏㄴ', 'ㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅓㅇㅑㅁㅏㄴ', 'ㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅏㅇㅑㅁㅏㄴ', 'ㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅓㅇㅑㅁㅏㄴ', 'ㅓㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅑㅁㅏㄴ', 'ㄷㅏ', [], ['v', 'adj', 'ida']),
+                suffixInflection('ㅇㅑㅁㅏㄴ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅕㅇㅑㅁㅏㄴ', 'ㅣㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅕㅇㅑㅁㅏㄴ', 'ㅇㅣㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅕㅇㅑㅁㅏㄴ', 'ㅇㅣㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅎㅐㅇㅑㅁㅏㄴ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅎㅏㅇㅕㅇㅑㅁㅏㄴ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅗㅏㅇㅑㅁㅏㄴ', 'ㅂㄷㅏ', [], ['v', 'adj']),
@@ -3589,12 +3589,12 @@ export const koreanTransforms = {
                 suffixInflection('ㅏㅇㅑㅈㅣ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅓㅇㅑㅈㅣ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅏㅇㅑㅈㅣ', 'ㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅓㅇㅑㅈㅣ', 'ㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅓㅇㅑㅈㅣ', 'ㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅏㅇㅑㅈㅣ', 'ㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅓㅇㅑㅈㅣ', 'ㅓㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅑㅈㅣ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅕㅇㅑㅈㅣ', 'ㅣㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅕㅇㅑㅈㅣ', 'ㅇㅣㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅕㅇㅑㅈㅣ', 'ㅇㅣㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅎㅐㅇㅑㅈㅣ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅎㅏㅇㅕㅇㅑㅈㅣ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅗㅏㅇㅑㅈㅣ', 'ㅂㄷㅏ', [], ['v', 'adj']),
@@ -3626,10 +3626,10 @@ export const koreanTransforms = {
                 suffixInflection('ㅏㅇㅛ', 'ㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅓㅇㅛ', 'ㅓㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅏㅇㅛ', 'ㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅓㅇㅛ', 'ㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅓㅇㅛ', 'ㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅇㅛ', 'ㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅕㅇㅛ', 'ㅣㄷㅏ', [], ['v', 'adj']),
-                suffixInflection('ㅇㅕㅇㅛ', 'ㅇㅣㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅕㅇㅛ', 'ㅇㅣㄷㅏ', [], ['v', 'adj', 'ida']),
                 suffixInflection('ㅎㅐㅇㅛ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅎㅏㅇㅕㅇㅛ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
                 suffixInflection('ㅇㅗㅏㅇㅛ', 'ㅂㄷㅏ', [], ['v', 'adj']),
@@ -3688,6 +3688,40 @@ export const koreanTransforms = {
                 suffixInflection('ㅇㅓㅈㅣㅇㅣㄷㅏ', '', [], ['p', 'f']),
             ],
         },
+        '-아/어지다': {
+            name: '-아/어지다',
+            rules: [
+                suffixInflection('ㅏㅈㅣㄷㅏ', 'ㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅓㅈㅣㄷㅏ', 'ㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅏㅈㅣㄷㅏ', 'ㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅓㅈㅣㄷㅏ', 'ㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅏㅈㅣㄷㅏ', 'ㅏㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅓㅈㅣㄷㅏ', 'ㅓㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅕㅈㅣㄷㅏ', 'ㅣㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅕㅈㅣㄷㅏ', 'ㅇㅣㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅎㅐㅈㅣㄷㅏ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅎㅏㅇㅕㅈㅣㄷㅏ', 'ㅎㅏㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅗㅏㅈㅣㄷㅏ', 'ㅂㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅜㅓㅈㅣㄷㅏ', 'ㅂㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅏㅈㅣㄷㅏ', 'ㅅㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅓㅈㅣㄷㅏ', 'ㅅㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅐㅈㅣㄷㅏ', 'ㅣㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅐㅈㅣㄷㅏ', 'ㅏㅎㄷㅏ', [], ['adj']),
+                suffixInflection('ㅐㅈㅣㄷㅏ', 'ㅓㅎㄷㅏ', [], ['adj']),
+                suffixInflection('ㅖㅈㅣㄷㅏ', 'ㅕㅎㄷㅏ', [], ['adj']),
+                suffixInflection('ㅒㅈㅣㄷㅏ', 'ㅑㅎㄷㅏ', [], ['adj']),
+                suffixInflection('ㄹㅇㅏㅈㅣㄷㅏ', 'ㄷㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㄹㅇㅓㅈㅣㄷㅏ', 'ㄷㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㄹㄹㅏㅈㅣㄷㅏ', 'ㄹㅡㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㄹㄹㅓㅈㅣㄷㅏ', 'ㄹㅡㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㄹㅡㄹㅓㅈㅣㄷㅏ', 'ㄹㅡㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅏㅈㅣㄷㅏ', 'ㅡㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅓㅈㅣㄷㅏ', 'ㅡㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅏㅈㅣㄷㅏ', 'ㅡㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅓㅈㅣㄷㅏ', 'ㅡㄷㅏ', [], ['v', 'adj']),
+                suffixInflection('ㅇㅓㅈㅣㄷㅏ', '', [], ['p', 'f']),
+            ],
+        },
         '-았/었': {
             name: '-았/었',
             rules: [
@@ -3796,8 +3830,8 @@ export const koreanTransforms = {
         '-야': {
             name: '-야',
             rules: [
-                suffixInflection('ㅇㅏㄴㅣㅇㅑ', '아니다', [], ['adj']),
-                suffixInflection('ㅇㅣㅇㅑ', '이다', [], ['ida']),
+                suffixInflection('ㅇㅏㄴㅣㅇㅑ', 'ㅇㅏㄴㅣㄷㅏ', [], ['adj']),
+                suffixInflection('ㅇㅣㅇㅑ', 'ㅇㅣㄷㅏ', [], ['ida']),
             ],
         },
         '-언마는': {
diff --git a/test/language/korean-transforms.test.js b/test/language/korean-transforms.test.js
index 10d6efef1..b3f32567d 100644
--- a/test/language/korean-transforms.test.js
+++ b/test/language/korean-transforms.test.js
@@ -690,11 +690,41 @@ const tests = [
             {term: '돕다', source: '돕자',     rule: 'v', reasons: ['-자']},
         ],
     },
+    {
+        category: '이다',
+        valid: true,
+        tests: [
+            {term: '이다', source: '이야',     rule: 'ida', reasons: ['-야']},
+
+
+            {term: '이다', source: '이어서',     rule: 'ida', reasons: ['-아/어서']},
+            {term: '이다', source: '이어야',     rule: 'ida', reasons: ['-아/어야']},
+            {term: '이다', source: '이어야겠',     rule: 'ida', reasons: ['-아/어야겠']},
+            {term: '이다', source: '이어야만',     rule: 'ida', reasons: ['-아/어야만']},
+            {term: '이다', source: '이어야지',     rule: 'ida', reasons: ['-아/어야지']},
+            {term: '이다', source: '이어요',     rule: 'ida', reasons: ['-아/어요']},
+
+            {term: '이다', source: '여서',     rule: 'ida', reasons: ['-아/어서']},
+            {term: '이다', source: '여야',     rule: 'ida', reasons: ['-아/어야']},
+            {term: '이다', source: '여야겠',     rule: 'ida', reasons: ['-아/어야겠']},
+            {term: '이다', source: '여야만',     rule: 'ida', reasons: ['-아/어야만']},
+            {term: '이다', source: '여야지',     rule: 'ida', reasons: ['-아/어야지']},
+            {term: '이다', source: '여요',     rule: 'ida', reasons: ['-아/어요']},
+        ],
+    },
     {
         category: 'invalid deinflections',
         valid: false,
         tests: [
             {term: '보다', source: '보십시다',     rule: 'v', reasons: ['-(으)시', '-(으)ㅂ시다']},
+
+            // ida
+            {term: '이다', source: '이서',     rule: 'ida', reasons: ['아/어서']},
+            {term: '이다', source: '이야',     rule: 'ida', reasons: ['아/어야']},
+            {term: '이다', source: '이야겠',     rule: 'ida', reasons: ['아/어야겠']},
+            {term: '이다', source: '이야만',     rule: 'ida', reasons: ['아/어야만']},
+            {term: '이다', source: '이야지',     rule: 'ida', reasons: ['아/어야지']},
+            {term: '이다', source: '이요',     rule: 'ida', reasons: ['아/어요']},
         ],
     },
 ];