diff --git a/components/GrammarTable.vue b/components/GrammarTable.vue
index 05b9d064e..a30406f6c 100644
--- a/components/GrammarTable.vue
+++ b/components/GrammarTable.vue
@@ -1,8 +1,12 @@
 <script setup lang="ts">
 import { loadGrammarTableVariantsConverter } from '~/src/data.ts';
 import type { Example, ExampleValues } from '~/src/language/examples.ts';
-import type { GrammarTableDefinition, Variant, SectionDefinition } from '~/src/language/grammarTables.ts';
-import { toMorphemeValue } from '~/src/language/morphemes.ts';
+import {
+    type GrammarTableDefinition,
+    type Variant,
+    type SectionDefinition,
+    expandVariantsForSection,
+} from '~/src/language/grammarTables.ts';
 
 const props = defineProps<{
     grammarTable: GrammarTableDefinition;
@@ -12,51 +16,15 @@ const props = defineProps<{
 
 const variantsFromBaseConverter = await loadGrammarTableVariantsConverter();
 
-const expandVariantsForSection = (sectionVariants: SectionDefinition['variants']): Variant[] => {
-    if (Array.isArray(sectionVariants)) {
-        return sectionVariants.map((sectionVariant) => {
-            const cells = sectionVariant.cells.map((cellDefinition) => {
-                if (cellDefinition === null) {
-                    return [];
-                }
-                if (typeof cellDefinition === 'string') {
-                    return [{ morpheme: cellDefinition }];
-                }
-                const cellPartDefinitions = Array.isArray(cellDefinition) ? cellDefinition : [cellDefinition];
-                return cellPartDefinitions
-                    .map((cellPartDefinition) => {
-                        if ('singular' in cellPartDefinition) {
-                            return cellPartDefinition[!props.exampleValues.plural ? 'singular' : 'plural'];
-                        }
-                        return cellPartDefinition;
-                    })
-                    .map((cellPartDefinition) => ({
-                        ...cellPartDefinition,
-                        prefix: cellPartDefinition.prefix ? toMorphemeValue(cellPartDefinition.prefix) : undefined,
-                        suffix: cellPartDefinition.suffix ? toMorphemeValue(cellPartDefinition.suffix) : undefined,
-                        highlightsMorphemes: cellPartDefinition.highlightsMorphemes
-                            ? new Set(cellPartDefinition.highlightsMorphemes)
-                            : undefined,
-                    }));
-            });
-            return { ...sectionVariant, cells };
-        });
-    } else {
-        if (Object.hasOwn(variantsFromBaseConverter, sectionVariants.type)) {
-            return variantsFromBaseConverter[sectionVariants.type](sectionVariants);
-        }
-        throw new Error(`variant type ${sectionVariants.type} is unknown`);
-    }
-};
-
 const buildVariantsForSection = (
     sectionVariants: SectionDefinition['variants'],
 ): Variant[] => {
-    return expandVariantsForSection(sectionVariants).filter((variant) => {
-        return variant.cells.flatMap((cell) => cell).some((cellPart) => {
-            return props.exampleValues.morphemeValues.getSpelling(cellPart.morpheme) !== undefined;
+    return expandVariantsForSection(sectionVariants, variantsFromBaseConverter, props.exampleValues)
+        .filter((variant) => {
+            return variant.cells.flatMap((cell) => cell).some((cellPart) => {
+                return props.exampleValues.morphemeValues.getSpelling(cellPart.morpheme) !== undefined;
+            });
         });
-    });
 };
 
 const sections = computed(() => {
diff --git a/src/data.ts b/src/data.ts
index 1ec054a87..af732eec7 100644
--- a/src/data.ts
+++ b/src/data.ts
@@ -23,9 +23,9 @@ export const loadTranslations = async (locale?: string): Promise<Translations> =
     return (await import(`~/locale/${locale ?? getLocale()}/translations.suml`)).default;
 };
 
-export const loadGrammarTableVariantsConverter = async () => {
+export const loadGrammarTableVariantsConverter = async (locale?: string) => {
     try {
-        return (await import(`~/locale/${getLocale()}/language/grammarTableVariantsConverter.ts`)).default as
+        return (await import(`~/locale/${locale ?? getLocale()}/language/grammarTableVariantsConverter.ts`)).default as
             VariantsFromBaseConverter;
     } catch (error) {
         return {};
diff --git a/src/language/grammarTables.ts b/src/language/grammarTables.ts
index b9e3c86c1..e6c97ca6c 100644
--- a/src/language/grammarTables.ts
+++ b/src/language/grammarTables.ts
@@ -1,4 +1,5 @@
-import type { MorphemeValue } from '~/src/language/morphemes.ts';
+import type { ExampleValues } from '~/src/language/examples.ts';
+import { type MorphemeValue, toMorphemeValue } from '~/src/language/morphemes.ts';
 
 export type GrammarTablesDefinition = (GrammarTableDefinition | string)[]
     | { simple: (GrammarTableDefinition | string)[]; comprehensive: (GrammarTableDefinition | string)[] };
@@ -56,3 +57,44 @@ export interface CellPart {
     prefix?: MorphemeValue;
     suffix?: MorphemeValue;
 }
+
+export const expandVariantsForSection = (
+    sectionVariants: SectionDefinition['variants'],
+    variantsFromBaseConverter: VariantsFromBaseConverter,
+    exampleValues: ExampleValues,
+): Variant[] => {
+    if (Array.isArray(sectionVariants)) {
+        return sectionVariants.map((sectionVariant) => {
+            const cells = sectionVariant.cells.map((cellDefinition) => {
+                if (cellDefinition === null) {
+                    return [];
+                }
+                if (typeof cellDefinition === 'string') {
+                    return [{ morpheme: cellDefinition }];
+                }
+                const cellPartDefinitions = Array.isArray(cellDefinition) ? cellDefinition : [cellDefinition];
+                return cellPartDefinitions
+                    .map((cellPartDefinition) => {
+                        if ('singular' in cellPartDefinition) {
+                            return cellPartDefinition[!exampleValues.plural ? 'singular' : 'plural'];
+                        }
+                        return cellPartDefinition;
+                    })
+                    .map((cellPartDefinition) => ({
+                        ...cellPartDefinition,
+                        prefix: cellPartDefinition.prefix ? toMorphemeValue(cellPartDefinition.prefix) : undefined,
+                        suffix: cellPartDefinition.suffix ? toMorphemeValue(cellPartDefinition.suffix) : undefined,
+                        highlightsMorphemes: cellPartDefinition.highlightsMorphemes
+                            ? new Set(cellPartDefinition.highlightsMorphemes)
+                            : undefined,
+                    }));
+            });
+            return { ...sectionVariant, cells };
+        });
+    } else {
+        if (Object.hasOwn(variantsFromBaseConverter, sectionVariants.type)) {
+            return variantsFromBaseConverter[sectionVariants.type](sectionVariants);
+        }
+        throw new Error(`variant type ${sectionVariants.type} is unknown`);
+    }
+};
diff --git a/test/language/grammarTables.ts b/test/language/grammarTables.ts
new file mode 100644
index 000000000..765dc0b0a
--- /dev/null
+++ b/test/language/grammarTables.ts
@@ -0,0 +1,49 @@
+import { expect } from 'vitest';
+
+import type { ExampleValues } from '~/src/language/examples.ts';
+import { expandVariantsForSection } from '~/src/language/grammarTables.ts';
+import type {
+    CellPart,
+    GrammarTableDefinition,
+    GrammarTablesDefinition, VariantsFromBaseConverter,
+} from '~/src/language/grammarTables.ts';
+import { MorphemeValues } from '~/src/language/morphemes.ts';
+
+const getGrammarTableDefinitions = (grammarTablesDefinition: GrammarTablesDefinition): GrammarTableDefinition[] => {
+    let grammarTableDefinitions: (GrammarTableDefinition | string)[];
+    if (Array.isArray(grammarTablesDefinition)) {
+        grammarTableDefinitions = grammarTablesDefinition;
+    } else {
+        grammarTableDefinitions = [...grammarTablesDefinition.simple, ...grammarTablesDefinition.comprehensive];
+    }
+    return grammarTableDefinitions.filter((grammarTableDefinition) => typeof grammarTableDefinition !== 'string');
+};
+
+const getCellParts = (
+    grammarTablesDefinition: GrammarTablesDefinition,
+    variantsFromBaseConverter: VariantsFromBaseConverter,
+    exampleValues: ExampleValues,
+): CellPart[] => {
+    return getGrammarTableDefinitions(grammarTablesDefinition)
+        .flatMap((grammarTableDefinition) => grammarTableDefinition.sections)
+        .flatMap((sectionDefinition) => {
+            return expandVariantsForSection(sectionDefinition.variants, variantsFromBaseConverter, exampleValues);
+        })
+        .flatMap((variant) => variant.cells)
+        .flatMap((cell) => cell);
+};
+
+export const checkContainsValidMorphemes = (
+    grammarTablesDefinition: GrammarTablesDefinition,
+    variantsFromBaseConverter: VariantsFromBaseConverter,
+    morphemes: string[],
+) => {
+    for (const plural of [false, true]) {
+        const exampleValues = { morphemeValues: new MorphemeValues({}), plural };
+        const cellParts = getCellParts(grammarTablesDefinition, variantsFromBaseConverter, exampleValues);
+        for (const cellPart of cellParts) {
+            expect(morphemes).toContain(cellPart.morpheme);
+            expect(morphemes).toEqual(expect.arrayContaining([...cellPart.highlightsMorphemes ?? []]));
+        }
+    }
+};
diff --git a/test/locales/config.test.ts b/test/locales/config.test.ts
index ab7459f15..afa8bddaf 100644
--- a/test/locales/config.test.ts
+++ b/test/locales/config.test.ts
@@ -5,11 +5,14 @@ import type { PronounData } from '~/locale/data.ts';
 import allLocales from '~/locale/locales.ts';
 import { loadSuml, loadTsv } from '~/server/loader.ts';
 import { parsePronouns } from '~/src/buildPronoun.ts';
+import { loadGrammarTableVariantsConverter } from '~/src/data.ts';
+import { checkContainsValidMorphemes } from '~/test/language/grammarTables.ts';
 
 describe.each(allLocales)('config for $code', async ({ code }) => {
     const config = await loadSuml<Config>(`locale/${code}/config.suml`);
     const pronounsRaw = await loadTsv<PronounData<string>>(`locale/${code}/pronouns/pronouns.tsv`);
     const pronouns = parsePronouns(config, pronounsRaw);
+    const variantsFromBaseConverter = await loadGrammarTableVariantsConverter(code);
 
     test('pronouns.generator.startPronoun must be a valid pronoun', () => {
         if (!config.pronouns.enabled || !config.pronouns.generator.enabled) {
@@ -29,4 +32,11 @@ describe.each(allLocales)('config for $code', async ({ code }) => {
         }
         expect(config.pronouns.morphemes).toEqual(expect.arrayContaining(Object.keys(config.pronouns.emoji.morphemes)));
     });
+    test('pronouns.grammarTables contain valid morphemes', () => {
+        if (!config.pronouns.enabled || !config.pronouns.grammarTables) {
+            return;
+        }
+
+        checkContainsValidMorphemes(config.pronouns.grammarTables, variantsFromBaseConverter, config.pronouns.morphemes);
+    });
 });