diff --git a/components/nouns/NounsClassExample.vue b/components/nouns/NounsClassExample.vue
index 6a03fe04e..e912f3f2a 100644
--- a/components/nouns/NounsClassExample.vue
+++ b/components/nouns/NounsClassExample.vue
@@ -33,20 +33,24 @@ const declension = computed(() => {
         return undefined;
     }
 
-    const declension = nounsData.declensions[template.value.declension];
-    if (!declension[numerus.value]) {
+    const declension = nounsData.declensions?.[template.value.declension];
+    if (declension?.[numerus.value] === undefined || nounsData.classExample?.[numerus.value] === undefined) {
         return undefined;
     }
 
     const entries = Object.entries(declension[numerus.value] ?? {}).map(([caseAbbreviation, declensionSuffix]) => {
-        return [caseAbbreviation.toUpperCase() + (props.plural ? '_pl' : ''),
-            nounsData.classExample[numerus.value][caseAbbreviation].replace(/\{([^}]+)}/, (_match, morpheme) => {
+        const article = nounsData.classExample?.[numerus.value][caseAbbreviation]
+            .replace(/\{([^}]+)}/, (_match, morpheme) => {
                 const value = props.nounConvention.morphemes[morpheme];
                 if (value === undefined) {
                     return '';
                 }
                 return typeof value === 'string' ? value : value.spelling;
-            }) + stem.value + template.value.suffix + declensionSuffix];
+            }) ?? '';
+        return [
+            caseAbbreviation.toUpperCase() + (props.plural ? '_pl' : ''),
+            article + stem.value + template.value.suffix + declensionSuffix,
+        ];
     });
 
     return new NounDeclension(Object.fromEntries(entries));
diff --git a/components/nouns/NounsConventionPage.vue b/components/nouns/NounsConventionPage.vue
index 906a7f14e..371379a9c 100644
--- a/components/nouns/NounsConventionPage.vue
+++ b/components/nouns/NounsConventionPage.vue
@@ -36,12 +36,12 @@ const examples = computed(() => {
     if (exampleValues.value === undefined) {
         return undefined;
     }
-    return nounsData?.examples.map((example) => Example.parse(example))
+    return nounsData.examples?.map((example) => Example.parse(example))
         .filter((example) => example.areRequiredExampleValuesPresent(exampleValues.value!));
 });
 
 const nounConventionGroup = computed(() => {
-    return Object.values(nounsData.groups).find((nounConventionGroup) => {
+    return Object.values(nounsData.groups ?? []).find((nounConventionGroup) => {
         return nounConventionGroup.conventions.includes(props.nounConvention.key);
     });
 });
diff --git a/components/nouns/NounsConventionsIndex.vue b/components/nouns/NounsConventionsIndex.vue
index 1ca14e991..1d1edf757 100644
--- a/components/nouns/NounsConventionsIndex.vue
+++ b/components/nouns/NounsConventionsIndex.vue
@@ -5,7 +5,7 @@ const nounsData = await loadNounsData();
 </script>
 
 <template>
-    <ul v-if="nounsData" class="list-group mt-4">
+    <ul v-if="nounsData.groups" class="list-group mt-4">
         <li
             v-for="nounConventionGroup of withKey(nounsData.groups)"
             :key="nounConventionGroup.key"
diff --git a/components/nouns/NounsConventionsIndexGroup.vue b/components/nouns/NounsConventionsIndexGroup.vue
index ee2478adf..31ea40fce 100644
--- a/components/nouns/NounsConventionsIndexGroup.vue
+++ b/components/nouns/NounsConventionsIndexGroup.vue
@@ -11,7 +11,7 @@ if (nounsData === undefined) {
     throw new Error('nounsData is undefined');
 }
 const visibleNounConventions = computed(() => {
-    return withKey(nounsData.conventions).filter((nounConvention) => {
+    return withKey(nounsData.conventions ?? {}).filter((nounConvention) => {
         return props.nounConventionGroup.conventions.includes(nounConvention.key);
     });
 });
diff --git a/components/nouns/NounsConventionsIndexItem.vue b/components/nouns/NounsConventionsIndexItem.vue
index 5310dd067..050bd867b 100644
--- a/components/nouns/NounsConventionsIndexItem.vue
+++ b/components/nouns/NounsConventionsIndexItem.vue
@@ -24,10 +24,10 @@ const stem = computed(() => {
     return stems[template.stem ?? 'default'];
 });
 
-const declension = nounsData.declensions[template.declension];
+const declension = nounsData.declensions?.[template.declension];
 
 const singularExample = computed(() => {
-    if (declension.singular?.n === undefined) {
+    if (declension?.singular?.n === undefined) {
         return undefined;
     }
 
@@ -35,7 +35,7 @@ const singularExample = computed(() => {
 });
 
 const pluralExample = computed(() => {
-    if (declension.plural?.n === undefined) {
+    if (declension?.plural?.n === undefined) {
         return undefined;
     }
 
diff --git a/components/nouns/NounsDeclension.vue b/components/nouns/NounsDeclension.vue
index b0cb4c3c0..fbc436e55 100644
--- a/components/nouns/NounsDeclension.vue
+++ b/components/nouns/NounsDeclension.vue
@@ -1,6 +1,6 @@
 <script setup lang="ts">
 import type { NounDeclension } from '~/src/classes.ts';
-import { loadNounDeclensionTemplates, loadNounCases } from '~/src/data.ts';
+import { loadNounDeclensionTemplates, loadNounsData } from '~/src/data.ts';
 
 const props = withDefaults(defineProps<{
     word: string;
@@ -14,7 +14,7 @@ const props = withDefaults(defineProps<{
     plural: false,
 });
 
-const [nounDeclensionTemplates, cases] = await Promise.all([loadNounDeclensionTemplates(), loadNounCases()]);
+const [nounsData, nounDeclensionTemplates] = await Promise.all([loadNounsData(), loadNounDeclensionTemplates()]);
 
 const visible = ref(props.open);
 
@@ -68,7 +68,7 @@ const findTemplate = (): NounDeclension | null => {
                 >
                     <strong>
                         {{ caseName }}
-                        <small v-if="!condense">({{ cases[caseName] }})</small>
+                        <small v-if="!condense">({{ nounsData.cases?.[caseName.toLowerCase()] }})</small>
                     </strong>
                     {{ declined.join(' / ') }}
                 </li>
diff --git a/locale/de/nouns/cases.ts b/locale/de/nouns/cases.ts
deleted file mode 100644
index a936a7088..000000000
--- a/locale/de/nouns/cases.ts
+++ /dev/null
@@ -1,6 +0,0 @@
-export default {
-    N: 'wer? was?',
-    G: 'wessen?',
-    D: 'wem?',
-    A: 'wen? was?',
-};
diff --git a/locale/de/nouns/nounsData.suml b/locale/de/nouns/nounsData.suml
index 21af97c74..a41ce587f 100644
--- a/locale/de/nouns/nounsData.suml
+++ b/locale/de/nouns/nounsData.suml
@@ -1,3 +1,9 @@
+cases:
+    n: 'wer? was?'
+    g: 'wessen?'
+    d: 'wem?'
+    a: 'wen? was?'
+
 morphemes:
     - 'article_n'
     - 'article_g'
diff --git a/locale/pl/nouns/cases.ts b/locale/pl/nouns/cases.ts
deleted file mode 100644
index 78ba66e53..000000000
--- a/locale/pl/nouns/cases.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-export default {
-    M: 'kto? co?',
-    D: 'kogo? czego?',
-    C: 'komu? czemu?',
-    B: 'kogo? co?',
-    N: 'z kim? z czym?',
-    Msc: 'o kim? o czym?',
-    W: 'o!',
-};
diff --git a/locale/pl/nouns/nounsData.suml b/locale/pl/nouns/nounsData.suml
new file mode 100644
index 000000000..895013007
--- /dev/null
+++ b/locale/pl/nouns/nounsData.suml
@@ -0,0 +1,8 @@
+cases:
+    m: 'kto? co?'
+    d: 'kogo? czego?'
+    c: 'komu? czemu?'
+    b: 'kogo? co?'
+    n: 'z kim? z czym?'
+    msc: 'o kim? o czym?'
+    w: 'o!'
diff --git a/locale/ru/nouns/cases.ts b/locale/ru/nouns/cases.ts
deleted file mode 100644
index 78ba66e53..000000000
--- a/locale/ru/nouns/cases.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-export default {
-    M: 'kto? co?',
-    D: 'kogo? czego?',
-    C: 'komu? czemu?',
-    B: 'kogo? co?',
-    N: 'z kim? z czym?',
-    Msc: 'o kim? o czym?',
-    W: 'o!',
-};
diff --git a/locale/ua/nouns/cases.ts b/locale/ua/nouns/cases.ts
deleted file mode 100644
index 78ba66e53..000000000
--- a/locale/ua/nouns/cases.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-export default {
-    M: 'kto? co?',
-    D: 'kogo? czego?',
-    C: 'komu? czemu?',
-    B: 'kogo? co?',
-    N: 'z kim? z czym?',
-    Msc: 'o kim? o czym?',
-    W: 'o!',
-};
diff --git a/middleware/languageItemFromPath.ts b/middleware/languageItemFromPath.ts
index 6473ec236..c09ddc10f 100644
--- a/middleware/languageItemFromPath.ts
+++ b/middleware/languageItemFromPath.ts
@@ -25,7 +25,7 @@ const findNounConvention = async (path: string, config: Config) => {
 
     const nounsData = await loadNounsData();
 
-    return withKey(nounsData?.conventions ?? {})
+    return withKey(nounsData.conventions ?? {})
         .find((nounConvention) => nounConvention.key === path);
 };
 
diff --git a/src/data.ts b/src/data.ts
index 4ba219dba..3efe95578 100644
--- a/src/data.ts
+++ b/src/data.ts
@@ -64,11 +64,11 @@ export const loadPronounLibrary = async (config: Config) => {
     return new PronounLibrary(config, pronounGroups, pronouns);
 };
 
-export const loadNounsData = async (): Promise<NounsData | undefined> => {
+export const loadNounsData = async (): Promise<NounsData> => {
     try {
         return (await import(`~/locale/${getLocale()}/nouns/nounsData.suml`)).default;
     } catch (error) {
-        return undefined;
+        return {};
     }
 };
 
@@ -109,14 +109,6 @@ export const loadNounAbbreviations = async (): Promise<Record<string, string>> =
     }
 };
 
-export const loadNounCases = async () => {
-    try {
-        return (await import(`~/locale/${getLocale()}/nouns/cases.ts`)).default;
-    } catch (error) {
-        return {};
-    }
-};
-
 export const loadPeople = async () => {
     const peopleRaw = (await import(`~/locale/${getLocale()}/people/people.tsv`)).default;
     return buildList(function* () {
diff --git a/src/nouns.ts b/src/nouns.ts
index 6d8156ad6..ee163c5b2 100644
--- a/src/nouns.ts
+++ b/src/nouns.ts
@@ -68,12 +68,13 @@ export interface NounDeclension {
 }
 
 export interface NounsData {
-    morphemes: string[];
-    examples: string[];
-    grammarTables: GrammarTableDefinition[];
-    classes: Record<string, NounClass>;
-    classExample: NounClassExample;
-    declensions: Record<string, NounDeclension>;
-    groups: Record<string, NounConventionGroup>;
-    conventions: Record<string, NounConvention>;
+    cases?: Record<string, string>;
+    morphemes?: string[];
+    examples?: string[];
+    grammarTables?: GrammarTableDefinition[];
+    classes?: Record<string, NounClass>;
+    classExample?: NounClassExample;
+    declensions?: Record<string, NounDeclension>;
+    groups?: Record<string, NounConventionGroup>;
+    conventions?: Record<string, NounConvention>;
 }
diff --git a/test/locales/data.test.ts b/test/locales/data.test.ts
index a186dd628..d39bd55fa 100644
--- a/test/locales/data.test.ts
+++ b/test/locales/data.test.ts
@@ -163,32 +163,64 @@ describe.each(allLocales)('data files of $code', async ({ code }) => {
         });
     }
 
-    if (config.nouns.conventions?.enabled) {
-        const nounsData = await loadSuml<NounsData>(`locale/${code}/nouns/nounsData.suml`);
+    let nounsData: NounsData | undefined;
+    try {
+        nounsData = await loadSuml<NounsData>(`locale/${code}/nouns/nounsData.suml`);
+    } catch (error) {
+        nounsData = undefined;
+    }
 
+    if (config.nouns.enabled && config.nouns.conventions?.enabled) {
+        test('config.nouns.conventions.enabled requires properties in nouns/nounsData.suml', () => {
+            expect(nounsData?.morphemes).toBeDefined();
+            expect(nounsData?.conventions).toBeDefined();
+            expect(nounsData?.groups).toBeDefined();
+            expect(nounsData?.classes).toBeDefined();
+            expect(nounsData?.classExample).toBeDefined();
+            expect(nounsData?.examples).toBeDefined();
+        });
+    }
+
+    if (nounsData) {
         describe('nouns/nounsData.suml', () => {
-            test('has valid variant types', async () => {
-                const grammarTableVariantsConverter = (await import(`~/locale/${code}/language/grammarTableVariantsConverter.ts`)).default as VariantsFromBaseConverter;
+            if (nounsData.grammarTables) {
+                test('grammar tables have valid variant types', async () => {
+                    const grammarTableVariantsConverter = (await import(`~/locale/${code}/language/grammarTableVariantsConverter.ts`)).default as VariantsFromBaseConverter;
 
-                for (const grammarTable of nounsData.grammarTables) {
-                    for (const section of grammarTable.sections) {
-                        if (!Array.isArray(section.variants)) {
-                            expect(Object.keys(grammarTableVariantsConverter)).toContain(section.variants.type);
+                    for (const grammarTable of nounsData.grammarTables!) {
+                        for (const section of grammarTable.sections) {
+                            if (!Array.isArray(section.variants)) {
+                                expect(Object.keys(grammarTableVariantsConverter)).toContain(section.variants.type);
+                            }
                         }
                     }
-                }
-            });
-            test('has valid morphemes', () => {
-                for (const convention of Object.values(nounsData.conventions)) {
-                    expect(nounsData.morphemes)
-                        .toEqual(expect.arrayContaining(Object.keys(convention.morphemes)));
-                }
-            });
-            test('groups reference conventions by key', () => {
-                for (const group of Object.values(nounsData.groups)) {
-                    expect(Object.keys(nounsData.conventions)).toEqual(expect.arrayContaining(group.conventions));
-                }
-            });
+                });
+            }
+            if (nounsData.conventions) {
+                test('conventions have valid morphemes', () => {
+                    for (const convention of Object.values(nounsData.conventions!)) {
+                        expect(nounsData.morphemes)
+                            .toEqual(expect.arrayContaining(Object.keys(convention.morphemes)));
+                    }
+                });
+            }
+            if (nounsData.conventions && nounsData.groups) {
+                test('convention groups reference conventions by key', () => {
+                    for (const group of Object.values(nounsData.groups!)) {
+                        expect(Object.keys(nounsData.conventions!)).toEqual(expect.arrayContaining(group.conventions));
+                    }
+                });
+            }
+            if (nounsData.cases && nounsData.declensions) {
+                test('declensions have valid cases', () => {
+                    for (const declension of Object.values(nounsData.declensions!)) {
+                        for (const numerus of ['singular', 'plural'] as const) {
+                            expect(Object.keys(nounsData.cases!))
+                                .toEqual(expect.arrayContaining(Object.keys(declension[numerus] ?? {})));
+                        }
+                    }
+                });
+            }
         });
     }
 });