diff --git a/package-lock.json b/package-lock.json
index dfa46510d..edd2aa042 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1404,6 +1404,11 @@
         "uri-js": "^4.2.2"
       }
     },
+    "ajv-i18n": {
+      "version": "3.6.0",
+      "resolved": "https://registry.npmjs.org/ajv-i18n/-/ajv-i18n-3.6.0.tgz",
+      "integrity": "sha512-F21DzmzYq9aVtY8CGGtlnQDy3rFMaFW2KRlMuCQp76KiPIkvqN+mpq5MI9EsgC0VFwj+jeLIsvVCvPOa1sobBQ=="
+    },
     "ajv-keywords": {
       "version": "3.5.2",
       "resolved": "https://registry.npmjs.org/ajv-keywords/-/ajv-keywords-3.5.2.tgz",
diff --git a/package.json b/package.json
index 37dbde886..c0383e7ce 100644
--- a/package.json
+++ b/package.json
@@ -28,10 +28,11 @@
   "dependencies": {
     "ace-builds": "^1.4.12",
     "ajv": "^6.12.6",
+    "ajv-i18n": "^3.6.0",
     "javascript-natural-sort": "^0.7.1",
     "jmespath": "^0.15.0",
-    "jsonrepair": "^2.0.0",
     "json-source-map": "^0.6.1",
+    "jsonrepair": "^2.0.0",
     "mobius1-selectr": "^2.4.13",
     "picomodal": "^3.0.0",
     "vanilla-picker": "^2.11.2"
diff --git a/src/js/textmode.js b/src/js/textmode.js
index 682faedb1..bcf1922b2 100644
--- a/src/js/textmode.js
+++ b/src/js/textmode.js
@@ -26,6 +26,7 @@ import {
   sortObjectKeys
 } from './util'
 import { validateCustom } from './validationUtils'
+import ajvLocalize from 'ajv-i18n'
 
 // create a mixin with the functions for text mode
 const textmode = {}
@@ -252,8 +253,8 @@ textmode.create = function (container, options = {}) {
 
   const emptyNode = {}
   const isReadOnly = (this.options.onEditable &&
-  typeof (this.options.onEditable === 'function') &&
-  !this.options.onEditable(emptyNode))
+        typeof (this.options.onEditable === 'function') &&
+        !this.options.onEditable(emptyNode))
 
   this.frame.appendChild(this.content)
   this.container.appendChild(this.frame)
@@ -843,6 +844,7 @@ textmode.validate = function () {
     if (this.validateSchema) {
       const valid = this.validateSchema(json)
       if (!valid) {
+        this._localizeErrors(this.validateSchema.errors)
         schemaErrors = this.validateSchema.errors.map(error => {
           error.type = 'validation'
           return improveSchemaError(error)
@@ -898,6 +900,15 @@ textmode.validate = function () {
   }
 }
 
+textmode._localizeErrors = function (errors) {
+  if (typeof this.options.language === 'string') {
+    const localize = ajvLocalize[this.options.language] || ajvLocalize.en
+    if (localize !== undefined && localize !== null) {
+      localize(errors)
+    }
+  }
+}
+
 textmode._renderErrors = function (errors) {
   const jsonText = this.getText()
   const errorPaths = []
diff --git a/src/js/treemode.js b/src/js/treemode.js
index 7692c71b7..e4769f36c 100644
--- a/src/js/treemode.js
+++ b/src/js/treemode.js
@@ -31,6 +31,7 @@ import {
   tryJsonRepair
 } from './util'
 import VanillaPicker from './vanilla-picker'
+import ajvLocalize from 'ajv-i18n'
 
 // create a mixin with the functions for tree mode
 const treemode = {}
@@ -154,7 +155,7 @@ treemode._setOptions = function (options) {
         }).show()
       } else {
         console.warn('Cannot open color picker: the `vanilla-picker` library is not included in the bundle. ' +
-            'Either use the full bundle or implement your own color picker using `onColorPicker`.')
+                    'Either use the full bundle or implement your own color picker using `onColorPicker`.')
       }
     },
     timestampTag: true,
@@ -567,6 +568,7 @@ treemode.validate = function () {
   if (this.validateSchema) {
     const valid = this.validateSchema(json)
     if (!valid) {
+      this._localizeValidationErrors(this.validateSchema.errors)
       // apply all new errors
       schemaErrors = this.validateSchema.errors
         .map(error => improveSchemaError(error))
@@ -610,6 +612,15 @@ treemode.validate = function () {
   }
 }
 
+treemode._localizeValidationErrors = function (errors) {
+  if (typeof this.options.language === 'string') {
+    const localize = ajvLocalize[this.options.language] || ajvLocalize.en
+    if (localize !== undefined && localize !== null) {
+      localize(errors)
+    }
+  }
+}
+
 treemode._renderValidationErrors = function (errorNodes) {
   // clear all current errors
   if (this.errorNodes) {
@@ -667,8 +678,8 @@ treemode._validateCustom = function (json) {
 
               if (!valid) {
                 console.warn('Ignoring a custom validation error with invalid structure. ' +
-                      'Expected structure: {path: [...], message: "..."}. ' +
-                      'Actual error:', error)
+                                    'Expected structure: {path: [...], message: "..."}. ' +
+                                    'Actual error:', error)
               }
 
               return valid
@@ -729,7 +740,7 @@ treemode.startAutoScroll = function (mouseY) {
   if ((mouseY < top + margin) && content.scrollTop > 0) {
     this.autoScrollStep = ((top + margin) - mouseY) / 3
   } else if (mouseY > bottom - margin &&
-      height + content.scrollTop < content.scrollHeight) {
+        height + content.scrollTop < content.scrollHeight) {
     this.autoScrollStep = ((bottom - margin) - mouseY) / 3
   } else {
     this.autoScrollStep = undefined
@@ -1271,7 +1282,7 @@ treemode._updateDragDistance = function (event) {
 
   this.dragDistanceEvent.dragDistance = Math.sqrt(diffX * diffX + diffY * diffY)
   this.dragDistanceEvent.hasMoved =
-      this.dragDistanceEvent.hasMoved || this.dragDistanceEvent.dragDistance > 10
+        this.dragDistanceEvent.hasMoved || this.dragDistanceEvent.dragDistance > 10
 
   event.dragDistance = this.dragDistanceEvent.dragDistance
   event.hasMoved = this.dragDistanceEvent.hasMoved
@@ -1549,11 +1560,11 @@ treemode._onKeyDown = function (event) {
     const me = this
     setTimeout(() => {
       /*
-          - Checking for change in focusTarget
-          - Without the check,
-            pressing tab after reaching the final DOM element in the editor will
-            set the focus back to it than passing focus outside the editor
-      */
+                - Checking for change in focusTarget
+                - Without the check,
+                  pressing tab after reaching the final DOM element in the editor will
+                  set the focus back to it than passing focus outside the editor
+            */
       if (me.focusTarget !== currentTarget) {
         // select all text when moving focus to an editable div
         selectContentEditable(me.focusTarget)