diff --git a/.eslintrc.js b/.eslintrc.js
index e79f87a5db..b7590a77eb 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -112,6 +112,7 @@ module.exports = {
         "getSerial": "readonly",
         "getTime": "readonly",
         "global": "readonly",
+        "globalThis": "readonly",
         "HIGH": "readonly",
         "I2C1": "readonly",
         "Infinity": "readonly",
diff --git a/apps/locale/locale.html b/apps/locale/locale.html
index 71bfecea95..5b370d735a 100644
--- a/apps/locale/locale.html
+++ b/apps/locale/locale.html
@@ -21,15 +21,17 @@
       <label><input id="customize" type="checkbox" /> Advanced: Customize the date and time formats.</label>
     </div>
     <p>
-      <span id="customize-warning"></span>
       <table id="examples-short-long"></table>
       <table id="examples"></table>
     </p>
 
+    <p id="customize-warning"></p>
+
     <p>Then click <button id="upload" class="btn btn-primary">Upload</button></p>
 
     <script src="../../core/lib/customize.js"></script>
     <script src="../../core/js/utils.js"></script>
+    <script src="sanitycheck.js"></script>
     <script src="locales.js"></script>
 
     <script>
@@ -103,32 +105,6 @@
         return '\\x'+(n+256).toString(16).slice(-2);
       }
 
-      // do some sanity checks
-      Object.keys(locales).forEach(function(localeName) {
-        var locale = locales[localeName];
-        if (locale.trans && !locale.trans.on) console.error(localeName+": If translations are provided, 'on' *must* be included");
-        if (distanceUnits[locale.distance[0]]===undefined) console.error(localeName+": Unknown distance unit "+locale.distance[0]);
-        if (distanceUnits[locale.distance[1]]===undefined) console.error(localeName+": Unknown distance unit "+locale.distance[1]);
-        if (speedUnits[locale.speed]===undefined) console.error(localeName+": Unknown speed unit "+locale.speed);
-        if (locale.temperature!='°C' && locale.temperature!='°F')
-          console.error(localeName+": Unknown temperature unit "+locale.temperature);
-        // Now check that codepage is ok and all chars in translation are in that codepage
-        const codePageName = "ISO8859-1";
-        if (locale.codePage) codePageName = locale.codePage;
-        const codePage = codePages[codePageName];
-        if (codePage===undefined) console.error(localeName+": Unknown codePage "+codePageName);
-        function checkChars(v,path) {
-          if ("object"==typeof v)
-            Object.keys(v).forEach(k=>checkChars(v[k], path+"."+k));
-          else if ("string"==typeof v)
-            for (var i=0;i<v.length;i++)
-              if (codePageLookup(localeName, codePage, v[i])===undefined)
-                console.error(` ... in ${path}[${i}]`);
-        }
-        checkChars(locale,localeName);
-      });
-
-
       function createLocaleModule() {
         console.log(`Language ${lang}`);
 
@@ -269,8 +245,6 @@
         }
 
         var date = new Date();
-        // TODO: This warning should have a link to an article explaining how the formats work, and how long they are allowed to be
-        document.getElementById("customize-warning").innerText = customizeLocale ? "⚠️ If you make the formats too long, some apps will not work!" : "";
         document.getElementById("examples-short-long").innerHTML = `
 <tr><td class="table_t"></td><td style="font-weight:bold">Short</td><td style="font-weight:bold">Long</td></tr>
 <tr><td class="table_t">Day</td><td>${exports.dow(date,1)}</td><td>${exports.dow(date,0)}</td></tr>
@@ -332,27 +306,63 @@
           document.querySelector("input#short-date-pattern").addEventListener("input", event => {
             locale.datePattern["1"] = event.target.value;
             document.querySelector("td#short-date-pattern-output").innerText = patternToOutput(event.target.value);
+            checkCustomLocale();
           });
           document.querySelector("input#long-date-pattern").addEventListener("input", event => {
             locale.datePattern["0"] = event.target.value;
             document.querySelector("td#long-date-pattern-output").innerText = patternToOutput(event.target.value);
+            checkCustomLocale();
           });
           document.querySelector("input#short-time-pattern").addEventListener("input", event => {
             locale.timePattern["1"] = event.target.value;
             document.querySelector("td#short-time-pattern-output").innerText = patternToOutput(event.target.value);
+            checkCustomLocale();
           });
           document.querySelector("input#long-time-pattern").addEventListener("input", event => {
             locale.timePattern["0"] = event.target.value;
             document.querySelector("td#long-time-pattern-output").innerText = patternToOutput(event.target.value);
+            checkCustomLocale();
           });
           document.querySelector("input#meridian-am").addEventListener("input", event => {
             locale.ampm["0"] = event.target.value;
             document.querySelector("span#meridian-am-output").innerText = event.target.value;
+            checkCustomLocale();
           });
           document.querySelector("input#meridian-pm").addEventListener("input", event => {
             locale.ampm["1"] = event.target.value;
             document.querySelector("span#meridian-pm-output").innerText = event.target.value;
+            checkCustomLocale();
           });
+
+          let isCheckingLocale = false;
+          // Polyfill for WebKit:
+          const requestIdleCallback = globalThis.requestIdleCallback || ((func) => {func()});
+          // Check that a custom locale follows some basic standards
+          function checkCustomLocale(){
+            if(isCheckingLocale) return;
+            isCheckingLocale = true;
+            setTimeout(() => {
+              requestIdleCallback(() => {
+                isCheckingLocale = false;
+                const result = globalThis.checkLocale(locale, {speedUnits, distanceUnits, codePages, CODEPAGE_CONVERSIONS});
+                let text = "";
+                for(const w of [...result.errors, ...result.warnings]){
+                  text += `⚠️ ${w.name} ${w.error}.\n`;
+                }
+                const element = document.getElementById("customize-warning");
+                if(text.length > 0){
+                  text += "\nIf you upload this locale, some apps might no longer work.\nPlease try to resolve the issues before uploading."
+                  element.classList.add("toast");
+                  element.classList.add("toast-error");
+                }else{
+                  element.classList.remove("toast");
+                  element.classList.remove("toast-error");
+                }
+                element.innerText = text;
+              }, {timeout: 2000})
+            }, 500);
+          }
+
         }
         return getLocaleModule(false);
       }
@@ -416,6 +426,10 @@
         }else{
           createLocaleModule();
         }
+        const warningsElement = document.getElementById("customize-warning")
+        warningsElement.innerText = "";
+        warningsElement.classList.remove("toast");
+        warningsElement.classList.remove("toast-error");
       }
       customizeSelector.addEventListener('change', handleCustomizeChange);
       function handleCustomizeChange(){
diff --git a/apps/locale/locales.js b/apps/locale/locales.js
index 11af6c1d81..8fbf428daf 100644
--- a/apps/locale/locales.js
+++ b/apps/locale/locales.js
@@ -536,7 +536,7 @@ var locales = {
     temperature: '°C',
     ampm: { 0: "öö", 1: "ös" },
     timePattern: { 0: "%HH:%MM:%SS", 1: "%HH:%MM" },
-    datePattern: { 0: "%d %w %Y %A", 1: "%d/%m/%Y" }, // 1 Mart 2020 Pazar // "01/03/2020"
+    datePattern: { 0: "%d %B %Y %A", 1: "%d/%m/%Y" }, // 1 Mart 2020 Pazar // "01/03/2020"
     abmonth: "Oca,Sub,Mar,Nis,May,Haz,Tem,Agu,Eyl,Eki,Kas,Ara",
     month: "Ocak,Subat,Mart,Nisan,Mayis,Haziran,Temmuz,Agustos,Eylul,Ekim,Kasim,Aralik",
     abday: "Paz,Pzt,Sal,Car,Per,Cum,Cmt",
diff --git a/apps/locale/sanitycheck.js b/apps/locale/sanitycheck.js
new file mode 100644
index 0000000000..192fa338aa
--- /dev/null
+++ b/apps/locale/sanitycheck.js
@@ -0,0 +1,233 @@
+/**
+ * Maps the Espruino datetime format to min and max character lengths.
+ * Used when determining if a format can produce outputs that are too short or long.
+ */
+const datetime_length_map = {
+	// %A, %a, %B, %b vary depending on the locale, so they are calculated later
+	"%Y": [4, 4],
+	"%y": [2, 2],
+	"%m": [2, 2],
+	"%-m": [1, 2],
+	"%d": [2, 2],
+	"%-d": [1, 2],
+	"%HH": [2, 2],
+	"%MM": [2, 2],
+	"%SS": [2, 2],
+};
+
+/**
+ * Takes an Espruino datetime format string and returns the minumum and maximum possible length of characters that the format could use.
+ *
+ * @param {string} datetimeEspruino - The datetime Espruino format
+ * @returns first the minimum possible length, second the maximum possible length.
+ */
+function getLengthOfDatetimeFormat(name, datetimeEspruino, locale, errors) {
+
+	// Generate the length_map based on the actual names in the locale
+	const length_map = {...datetime_length_map};
+	for(const [symbol, values] of [
+		["%A", locale.day],
+		["%a", locale.abday],
+		["%B", locale.month],
+		["%b", locale.abmonth],
+	]){
+		const length = [Infinity, 0];
+		for(const value of values.split(",")){
+			if(length[0] > value.length) length[0] = value.length;
+			if(length[1] < value.length) length[1] = value.length;
+		}
+		length_map[symbol] = length;
+	}
+
+	// Find the length of the output
+	let formatLength = [0, 0];
+	let i = 0;
+	while (i < datetimeEspruino.length) {
+		if (datetimeEspruino[i] === "%") {
+			let match;
+			for(const symbolLength of [2, 3]){
+				const length = length_map[datetimeEspruino.substring(i, i+symbolLength)];
+				if(length){
+					match = {
+						length,
+						symbolLength,
+					}
+				}
+			}
+			if(match){
+				formatLength[0] += match.length[0];
+				formatLength[1] += match.length[1];
+				i += match.symbolLength;
+			}else{
+				errors.push({name, value: datetimeEspruino, lang: locale.lang, error: `uses an unsupported format symbol: ${datetimeEspruino.substring(i, i+3)}`});
+				formatLength[0]++;
+				formatLength[1]++;
+				i++;
+			}
+		} else {
+			formatLength[0]++;
+			formatLength[1]++;
+			i++;
+		}
+	}
+	return formatLength;
+}
+
+/**
+ * Checks that a locale conforms to some basic standards.
+ *
+ * @param {object} locale - The locale to test.
+ * @param {object} meta - Meta information that is needed to check if locales are supported.
+ * @param {object} meta.speedUnits - The table of speed units.
+ * @param {object} meta.distanceUnits - The table of distance units.
+ * @param {object} meta.codePages - Custom codepoint mappings.
+ * @param {object} meta.CODEPAGE_CONVERSIONS - The table of custom codepoint conversions.
+ * @returns an object with an array of errors and warnings.
+ */
+function checkLocale(locale, {speedUnits, distanceUnits, codePages, CODEPAGE_CONVERSIONS}){
+	const errors = [];
+	const warnings = [];
+
+	const speeds = Object.keys(speedUnits);
+	const distances = Object.keys(distanceUnits);
+
+	checkLength("lang", locale.lang, 5, undefined);
+	checkLength("decimal point", locale.decimal_point, 1, 1);
+	checkLength("thousands separator", locale.thousands_sep, 1, 1);
+	checkLength("speed", locale.speed, 2, 4);
+	checkIsIn("speed", locale.speed, "speedUnits", speeds);
+	checkLength("distance", locale.distance["0"], 1, 3);
+	checkLength("distance", locale.distance["1"], 1, 3);
+	checkIsIn("distance", locale.distance["0"], "distanceUnits", distances);
+	checkIsIn("distance", locale.distance["1"], "distanceUnits", distances);
+	checkLength("temperature", locale.temperature, 1, 2);
+	checkLength("meridian", locale.ampm["0"], 1, 3);
+	checkLength("meridian", locale.ampm["1"], 1, 3);
+	warnIfNot("long time format", locale.timePattern["0"], "%HH:%MM:%SS");
+	warnIfNot("short time format", locale.timePattern["1"], "%HH:%MM");
+	checkFormatLength("long time", locale.timePattern["0"], 8, 8);
+	checkFormatLength("short time", locale.timePattern["1"], 5, 5);
+	checkFormatLength("long date", locale.datePattern["0"], 6, 14);
+	checkFormatLength("short date", locale.datePattern["1"], 6, 11);
+	checkArrayLength("short months", locale.abmonth.split(","), 12, 12);
+	checkArrayLength("long months", locale.month.split(","), 12, 12);
+	checkArrayLength("short days", locale.abday.split(","), 7, 7);
+	checkArrayLength("long days", locale.day.split(","), 7, 7);
+	for (const abmonth of locale.abmonth.split(",")) {
+		checkLength("short month", abmonth, 2, 4);
+	}
+	for (const month of locale.month.split(",")) {
+		checkLength("month", month, 3, 11);
+	}
+	for (const abday of locale.abday.split(",")) {
+		checkLength("short day", abday, 2, 4);
+	}
+	for (const day of locale.day.split(",")) {
+		checkLength("day", day, 3, 13);
+	}
+	checkEncoding(locale);
+
+	function checkLength(name, value, min, max) {
+		if(typeof value !== "string"){
+			errors.push({name, value, lang: locale.lang, error: `must be defined and must be a string`});
+			return;
+		}
+		if (min && value.length < min) {
+			errors.push({name, value, lang: locale.lang, error: `must be longer than ${min-1} characters`});
+		}
+		if (max && value.length > max) {
+			errors.push({name, value, lang: locale.lang, error: `must be shorter than ${max+1} characters`});
+		}
+	}
+	function checkArrayLength(name, value, min, max){
+		if(!Array.isArray(value)){
+			errors.push({name, value, lang: locale.lang, error: `must be defined and must be an array`});
+			return;
+		}
+		if (min && value.length < min) {
+			errors.push({name, value, lang: locale.lang, error: `array must be longer than ${min-1} entries`});
+		}
+		if (max && value.length > max) {
+			errors.push({name, value, lang: locale.lang, error: `array must be shorter than ${max+1} entries`});
+		}
+	}
+	function checkFormatLength(name, value, min, max) {
+		const length = getLengthOfDatetimeFormat(name, value, locale, errors);
+		if (min && length[0] < min) {
+			errors.push({name, value, lang: locale.lang, error: `output must be longer than ${min-1} characters`});
+		}
+		if (max && length[1] > max) {
+			errors.push({name, value, lang: locale.lang, error: `output must be shorter than ${max+1} characters`});
+		}
+	}
+	function checkIsIn(name, value, listName, list) {
+		if (!list.includes(value)) {
+			errors.push({name, value, lang: locale.lang, error: `must be included in the ${listName} map`});
+		}
+	}
+	function warnIfNot(name, value, expected) {
+		if (value !== expected) {
+			warnings.push({name, value, lang: locale.lang, error: `might not work in some apps if it is not "${expected}"`});
+		}
+	}
+	function checkEncoding(object) {
+		if(!object){
+			return;
+		}else if(typeof object === "string"){
+			for(const char of object){
+				const charCode = char.charCodeAt();
+				if (charCode >= 32 && charCode < 128) {
+					// ASCII - fully supported
+					continue;
+				} else if (codePages["ISO8859-1"].map.indexOf(char) >= 0) {
+					// At upload time, the char can be converted to a custom codepage
+					continue;
+				} else if (CODEPAGE_CONVERSIONS[char]) {
+					// At upload time, the char can be converted to a similar supported char
+					continue;
+				}
+				errors.push({name: `character ${char}`, value: char, lang: locale.lang, error: `is not supported by BangleJS`});
+			}
+		}else{
+			for(const [key, value] of Object.entries(object)){
+				if(key === "icon") continue;
+				checkEncoding(value);
+			}
+		}
+	}
+
+	return {errors, warnings};
+}
+
+/**
+ * Checks that an array of locales conform to some basic standards.
+ *
+ * @param {object[]} locales - The locales to test.
+ * @param {object} meta.speedUnits - The table of speed units.
+ * @param {object} meta.distanceUnits - The table of distance units.
+ * @param {object} meta.codePages - Custom codepoint mappings.
+ * @param {object} meta.CODEPAGE_CONVERSIONS - The table of custom codepoint conversions.
+ * @returns an object with an array of errors and warnings.
+ */
+function checkLocales(locales, meta){
+	let errors = [];
+	let warnings = [];
+
+	for(const locale of Object.values(locales)){
+		const result = checkLocale(locale, meta);
+		errors = [...errors, ...result.errors];
+		warnings = [...warnings, ...result.warnings];
+	}
+
+	return {errors, warnings};
+}
+
+if(typeof module !== "undefined"){
+	module.exports = {
+		checkLocale,
+		checkLocales,
+	};
+}else{
+	globalThis.checkLocale = checkLocale;
+	globalThis.checkLocales = checkLocales;
+}
diff --git a/bin/sanitycheck.js b/bin/sanitycheck.js
index 0415406065..eceb0d4918 100755
--- a/bin/sanitycheck.js
+++ b/bin/sanitycheck.js
@@ -3,6 +3,7 @@
 */
 
 var fs = require("fs");
+var vm = require("vm");
 var heatshrink = require("../webtools/heatshrink");
 var acorn;
 try {
@@ -20,13 +21,19 @@ var BASEDIR = __dirname+"/../";
 var APPSDIR_RELATIVE = "apps/";
 var APPSDIR = BASEDIR + APPSDIR_RELATIVE;
 var knownWarningCount = 0;
+var knownErrorCount = 0;
 var warningCount = 0;
 var errorCount = 0;
 function ERROR(msg, opt) {
   // file=app.js,line=1,col=5,endColumn=7
   opt = opt||{};
-  console.log(`::error${Object.keys(opt).length?" ":""}${Object.keys(opt).map(k=>k+"="+opt[k]).join(",")}::${msg}`);
-  errorCount++;
+  if (KNOWN_ERRORS.includes(msg)) {
+    console.log(`Known error : ${msg}`);
+    knownErrorCount++;
+  } else {
+    console.log(`::error${Object.keys(opt).length?" ":""}${Object.keys(opt).map(k=>k+"="+opt[k]).join(",")}::${msg}`);
+    errorCount++;
+  }
 }
 function WARN(msg, opt) {
   // file=app.js,line=1,col=5,endColumn=7
@@ -39,6 +46,71 @@ function WARN(msg, opt) {
     warningCount++;
   }
 }
+/* These are errors that we temporarily allow */
+var KNOWN_ERRORS = [
+  "In locale en_CA, long date output must be shorter than 15 characters",
+  "In locale fr_FR, long date output must be shorter than 15 characters",
+  "In locale en_SE, long date output must be shorter than 15 characters",
+  "In locale en_NZ, long date output must be shorter than 15 characters",
+  "In locale en_AU, long date output must be shorter than 15 characters",
+  "In locale de_AT, long date output must be shorter than 15 characters",
+  "In locale en_IL, long date output must be shorter than 15 characters",
+  "In locale es_ES, long date output must be shorter than 15 characters",
+  "In locale fr_BE, long date output must be shorter than 15 characters",
+  "In locale fi_FI, long date output must be shorter than 15 characters",
+  "In locale de_CH, long date output must be shorter than 15 characters",
+  "In locale fr_CH, long date output must be shorter than 15 characters",
+  "In locale wae_CH, long date output must be shorter than 15 characters",
+  "In locale tr_TR, long date output must be shorter than 15 characters",
+  "In locale hu_HU, long date output must be shorter than 15 characters",
+  "In locale oc_FR, long date output must be shorter than 15 characters",
+  "In locale ca_ES, long date output must be shorter than 15 characters",
+  "In locale fr_BE, short month must be shorter than 5 characters",
+  "In locale fi_FI, short month must be shorter than 5 characters",
+  "In locale fr_CH, short month must be shorter than 5 characters",
+  "In locale oc_FR, short month must be shorter than 5 characters",
+  "In locale hr_HR, short month must be shorter than 5 characters",
+  "In locale ca_ES, short month must be shorter than 5 characters",
+  "In locale de_DE, meridian must be longer than 0 characters",
+  "In locale en_JP, meridian must be longer than 0 characters",
+  "In locale nl_NL, meridian must be longer than 0 characters",
+  "In locale fr_FR, meridian must be longer than 0 characters",
+  "In locale se_SE, meridian must be longer than 0 characters",
+  "In locale en_SE, meridian must be longer than 0 characters",
+  "In locale da_DK, meridian must be longer than 0 characters",
+  "In locale en_DK, meridian must be longer than 0 characters",
+  "In locale de_AT, meridian must be longer than 0 characters",
+  "In locale es_ES, meridian must be longer than 0 characters",
+  "In locale fr_BE, meridian must be longer than 0 characters",
+  "In locale it_CH, meridian must be longer than 0 characters",
+  "In locale it_IT, meridian must be longer than 0 characters",
+  "In locale wae_CH, meridian must be longer than 0 characters",
+  "In locale oc_FR, meridian must be longer than 0 characters",
+  "In locale pl_PL, meridian must be longer than 0 characters",
+  "In locale lv_LV, meridian must be longer than 0 characters",
+  "In locale nn_NO, meridian must be longer than 0 characters",
+  "In locale nb_NO, meridian must be longer than 0 characters",
+  "In locale ca_ES, meridian must be longer than 0 characters",
+  "In locale de_CH, meridian must be shorter than 4 characters",
+  "In locale hr_HR, meridian must be shorter than 4 characters",
+  "In locale sl_SI, meridian must be shorter than 4 characters",
+  "In locale fr_FR, short month must be shorter than 5 characters",
+  "In locale sv_SE, speed must be shorter than 5 characters",
+];
+/* These are warnings we know about but don't want in our output */
+var KNOWN_WARNINGS = [
+  "App gpsrec data file wildcard .gpsrc? does not include app ID",
+  "App owmweather data file weather.json is also listed as data file for app weather",
+  "App messagegui storage file messagegui is also listed as storage file for app messagelist",
+  "App carcrazy has a setting file but no corresponding data entry (add `\"data\":[{\"name\":\"carcrazy.settings.json\"}]`)",
+  "App loadingscreen has a setting file but no corresponding data entry (add `\"data\":[{\"name\":\"loadingscreen.settings.json\"}]`)",
+  "App trex has a setting file but no corresponding data entry (add `\"data\":[{\"name\":\"trex.settings.json\"}]`)",
+  "widhwt isn't an app (widget) but has an app.js file (widhwtapp.js)",
+  `In locale it_CH, long time format might not work in some apps if it is not "%HH:%MM:%SS"`,
+  `In locale it_IT, long time format might not work in some apps if it is not "%HH:%MM:%SS"`,
+  `In locale wae_CH, long time format might not work in some apps if it is not "%HH:%MM:%SS"`,
+  `In locale wae_CH, short time format might not work in some apps if it is not "%HH:%MM"`,
+];
 
 var apps = [];
 var dirs = fs.readdirSync(APPSDIR, {withFileTypes: true});
@@ -91,16 +163,6 @@ const INTERNAL_FILES_IN_APP_TYPE = { // list of app types and files they SHOULD
   'textinput' : ['textinput'],
   // notify?
 };
-/* These are warnings we know about but don't want in our output */
-var KNOWN_WARNINGS = [
-  "App gpsrec data file wildcard .gpsrc? does not include app ID",
-  "App owmweather data file weather.json is also listed as data file for app weather",
-  "App messagegui storage file messagegui is also listed as storage file for app messagelist",
-  "App carcrazy has a setting file but no corresponding data entry (add `\"data\":[{\"name\":\"carcrazy.settings.json\"}]`)",
-  "App loadingscreen has a setting file but no corresponding data entry (add `\"data\":[{\"name\":\"loadingscreen.settings.json\"}]`)",
-  "App trex has a setting file but no corresponding data entry (add `\"data\":[{\"name\":\"trex.settings.json\"}]`)",
-  "widhwt isn't an app (widget) but has an app.js file (widhwtapp.js)",
-];
 
 function globToRegex(pattern) {
   const ESCAPE = '.*+-?^${}()|[]\\';
@@ -397,8 +459,28 @@ while(fileA=allFiles.pop()) {
   })
 }
 
+// Check each locale in the `locale` app.
+sanityCheckLocales();
+function sanityCheckLocales(){
+  const { CODEPAGE_CONVERSIONS } = require("../core/js/utils");
+  const { checkLocales } = require("../apps/locale/sanitycheck");
+  const localesCode = fs.readFileSync(__dirname+'/../apps/locale/locales.js', 'utf-8');
+  vm.runInThisContext(localesCode);
+  /* global locales, speedUnits, distanceUnits, codePages */
+
+  const {errors, warnings} = checkLocales(locales, {speedUnits, distanceUnits, codePages, CODEPAGE_CONVERSIONS});
+
+  const file = "locale/locales.js";
+  for(const w of warnings){
+    WARN(`In locale ${w.lang}, ${w.name} ${w.error}`, {file, value: w.value});
+  }
+  for(const e of errors){
+    ERROR(`In locale ${e.lang}, ${e.name} ${e.error}`, {file, value: e.value});
+  }
+}
+
 console.log("==================================");
-console.log(`${errorCount} errors, ${warningCount} warnings (and ${knownWarningCount} known warnings)`);
+console.log(`${errorCount} errors, ${warningCount} warnings (and ${knownErrorCount} known errors, ${knownWarningCount} known warnings)`);
 console.log("==================================");
 if (errorCount)  {
   process.exit(1);