diff --git a/lib/controller/multi-language.ts b/lib/controller/multi-language.ts
index 68984a1..ebae77c 100644
--- a/lib/controller/multi-language.ts
+++ b/lib/controller/multi-language.ts
@@ -1,4 +1,5 @@
 /* eslint-disable @typescript-eslint/method-signature-style */
+import DeepMerge from '@fastify/deepmerge'
 import AggregateBuilder from '@kakang/mongodb-aggregate-builder'
 import { isEmpty, isExist, isNull, isUndefined } from '@kakang/validator'
 import { type AggregateOptions, type AnyBulkWriteOperation, type BulkWriteOptions, type Collection, type Document, type Filter, type FindOptions, type UpdateFilter } from 'mongodb'
@@ -6,6 +7,7 @@ import { appendBasicSchema, appendUpdateSchema } from '../utils/append'
 import { computeSharedOption } from '../utils/option'
 import { normalizeQueryDate, retrieveUpdateQueryData } from '../utils/query'
 import { Controller, type ControllerOptions, type SearchOptions } from './default'
+const deepmerge = DeepMerge()
 
 export interface MultiLanguageControllerOptions<TSchema extends Document = Document> extends Partial<ControllerOptions> {
   slugField: keyof TSchema
@@ -64,8 +66,10 @@ export class MultiLanguageController<TSchema extends Document = Document> extend
 
     // insert when it is fallback, update when item exist
     if (isFallback) {
+      // we need to merge the old and new document to prevent missing fields
+      const doc: any = deepmerge(item, retrieveUpdateQueryData(docs))
       // we append needed info for the document
-      const document: any = appendBasicSchema(retrieveUpdateQueryData(docs), this.appendBasicSchema)
+      const document: any = appendBasicSchema(doc as TSchema, this.appendBasicSchema)
       // ensure slug is exist
       document[this.slugField] = item[this.slugField]
       // insert if language is not exist
diff --git a/package.json b/package.json
index 792cbd7..17202ae 100644
--- a/package.json
+++ b/package.json
@@ -55,6 +55,7 @@
     "typescript": "~5.3.3"
   },
   "dependencies": {
+    "@fastify/deepmerge": "^1.3.0",
     "@kakang/eventemitter": "^0.2.1",
     "@kakang/mongodb-aggregate-builder": "^0.2.2",
     "@kakang/validator": "^0.1.4",