diff --git a/.env.example b/.env.example
index 25a959d3bb..9a4ad1ba45 100644
--- a/.env.example
+++ b/.env.example
@@ -12,6 +12,7 @@ CACHE_DRIVER=file
 SESSION_DRIVER=file
 
 DEFAULT_CURRENCY=EUR
+DEFAULT_LANGUAGE=en_US
 
 EMAIL_SMTP=
 EMAIL_DRIVER=smtp
diff --git a/app/Generator/Chart/Account/ChartJsAccountChartGenerator.php b/app/Generator/Chart/Account/ChartJsAccountChartGenerator.php
index ec8460cdfd..280c0a2bdc 100644
--- a/app/Generator/Chart/Account/ChartJsAccountChartGenerator.php
+++ b/app/Generator/Chart/Account/ChartJsAccountChartGenerator.php
@@ -105,7 +105,7 @@ class ChartJsAccountChartGenerator implements AccountChartGenerator
     public function frontpage(Collection $accounts, Carbon $start, Carbon $end)
     {
         // language:
-        $language = Preferences::get('language', 'en')->data;
+        $language = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $format   = Config::get('firefly.monthAndDay.' . $language);
         $data     = [
             'count'    => 0,
@@ -151,7 +151,7 @@ class ChartJsAccountChartGenerator implements AccountChartGenerator
     public function single(Account $account, Carbon $start, Carbon $end)
     {
         // language:
-        $language = Preferences::get('language', 'en')->data;
+        $language = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $format   = Config::get('firefly.monthAndDay.' . $language);
 
         $data = [
diff --git a/app/Generator/Chart/Bill/ChartJsBillChartGenerator.php b/app/Generator/Chart/Bill/ChartJsBillChartGenerator.php
index 8a63f803aa..972944763f 100644
--- a/app/Generator/Chart/Bill/ChartJsBillChartGenerator.php
+++ b/app/Generator/Chart/Bill/ChartJsBillChartGenerator.php
@@ -71,7 +71,7 @@ class ChartJsBillChartGenerator implements BillChartGenerator
     public function single(Bill $bill, Collection $entries)
     {
         // language:
-        $language = Preferences::get('language', 'en')->data;
+        $language = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $format   = Config::get('firefly.month.' . $language);
 
         $data = [
diff --git a/app/Generator/Chart/Budget/ChartJsBudgetChartGenerator.php b/app/Generator/Chart/Budget/ChartJsBudgetChartGenerator.php
index 9bc1d28877..d0952216c9 100644
--- a/app/Generator/Chart/Budget/ChartJsBudgetChartGenerator.php
+++ b/app/Generator/Chart/Budget/ChartJsBudgetChartGenerator.php
@@ -24,7 +24,7 @@ class ChartJsBudgetChartGenerator implements BudgetChartGenerator
     public function budget(Collection $entries, $dateFormat = 'month')
     {
         // language:
-        $language = Preferences::get('language', 'en')->data;
+        $language = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $format   = Config::get('firefly.' . $dateFormat . '.' . $language);
 
         $data = [
@@ -115,7 +115,7 @@ class ChartJsBudgetChartGenerator implements BudgetChartGenerator
     public function year(Collection $budgets, Collection $entries)
     {
         // language:
-        $language = Preferences::get('language', 'en')->data;
+        $language = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $format   = Config::get('firefly.month.' . $language);
 
         $data = [
diff --git a/app/Generator/Chart/Category/ChartJsCategoryChartGenerator.php b/app/Generator/Chart/Category/ChartJsCategoryChartGenerator.php
index 07eb4e0f31..cac74e488e 100644
--- a/app/Generator/Chart/Category/ChartJsCategoryChartGenerator.php
+++ b/app/Generator/Chart/Category/ChartJsCategoryChartGenerator.php
@@ -101,7 +101,7 @@ class ChartJsCategoryChartGenerator implements CategoryChartGenerator
     {
 
         // language:
-        $language = Preferences::get('language', 'en')->data;
+        $language = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $format   = Config::get('firefly.month.' . $language);
 
         $data = [
@@ -135,7 +135,7 @@ class ChartJsCategoryChartGenerator implements CategoryChartGenerator
     {
 
         // language:
-        $language = Preferences::get('language', 'en')->data;
+        $language = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $format   = Config::get('firefly.month.' . $language);
 
         $data = [
diff --git a/app/Generator/Chart/PiggyBank/ChartJsPiggyBankChartGenerator.php b/app/Generator/Chart/PiggyBank/ChartJsPiggyBankChartGenerator.php
index 8927d1bb91..e1aa9fb352 100644
--- a/app/Generator/Chart/PiggyBank/ChartJsPiggyBankChartGenerator.php
+++ b/app/Generator/Chart/PiggyBank/ChartJsPiggyBankChartGenerator.php
@@ -25,7 +25,7 @@ class ChartJsPiggyBankChartGenerator implements PiggyBankChartGenerator
     {
 
         // language:
-        $language = Preferences::get('language', 'en')->data;
+        $language = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $format   = Config::get('firefly.monthAndDay.' . $language);
 
         $data = [
diff --git a/app/Generator/Chart/Report/ChartJsReportChartGenerator.php b/app/Generator/Chart/Report/ChartJsReportChartGenerator.php
index 0b2250b39a..8cd93f3ccf 100644
--- a/app/Generator/Chart/Report/ChartJsReportChartGenerator.php
+++ b/app/Generator/Chart/Report/ChartJsReportChartGenerator.php
@@ -22,7 +22,7 @@ class ChartJsReportChartGenerator implements ReportChartGenerator
     public function yearInOut(Collection $entries)
     {
         // language:
-        $language = Preferences::get('language', 'en')->data;
+        $language = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $format   = Config::get('firefly.month.' . $language);
 
         $data = [
diff --git a/app/Http/Controllers/Controller.php b/app/Http/Controllers/Controller.php
index 03a9a8d31c..d733973e30 100644
--- a/app/Http/Controllers/Controller.php
+++ b/app/Http/Controllers/Controller.php
@@ -34,7 +34,7 @@ abstract class Controller extends BaseController
         View::share('hideTags', false);
 
         if (Auth::check()) {
-            $pref                    = Preferences::get('language', 'en');
+            $pref                    = Preferences::get('language',env('DEFAULT_LANGUAGE','en_US'));
             $lang                    = $pref->data;
             $this->monthFormat       = Config::get('firefly.month.' . $lang);
             $this->monthAndDayFormat = Config::get('firefly.monthAndDay.' . $lang);
diff --git a/app/Http/Controllers/PreferencesController.php b/app/Http/Controllers/PreferencesController.php
index 8bfd176f53..9fd0cb95b9 100644
--- a/app/Http/Controllers/PreferencesController.php
+++ b/app/Http/Controllers/PreferencesController.php
@@ -37,7 +37,7 @@ class PreferencesController extends Controller
         $viewRange         = $viewRangePref->data;
         $frontPageAccounts = Preferences::get('frontPageAccounts', []);
         $budgetMax         = Preferences::get('budgetMaximum', 1000);
-        $language          = Preferences::get('language', 'en')->data;
+        $language          = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
         $budgetMaximum     = $budgetMax->data;
 
         return view('preferences.index', compact('budgetMaximum', 'language', 'accounts', 'frontPageAccounts', 'viewRange'));
diff --git a/app/Http/Middleware/Authenticate.php b/app/Http/Middleware/Authenticate.php
index 458e19f62d..0205f06ba6 100644
--- a/app/Http/Middleware/Authenticate.php
+++ b/app/Http/Middleware/Authenticate.php
@@ -61,7 +61,7 @@ class Authenticate
         }
 
         // if logged in, set user language:
-        $pref = Preferences::get('language', 'en');
+        $pref = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'));
         App::setLocale($pref->data);
         Carbon::setLocale($pref->data);
 
diff --git a/app/Http/breadcrumbs.php b/app/Http/breadcrumbs.php
index 3494c7a1f7..6030da8875 100644
--- a/app/Http/breadcrumbs.php
+++ b/app/Http/breadcrumbs.php
@@ -354,7 +354,7 @@ Breadcrumbs::register(
     'reports.report', function (Generator $breadcrumbs, Carbon $start, Carbon $end, $reportType, $accountIds) {
     $breadcrumbs->parent('reports.index');
 
-    $pref        = Preferences::get('language', 'en')->data;
+    $pref        = Preferences::get('language', env('DEFAULT_LANGUAGE','en_US'))->data;
     $monthFormat = Config::get('firefly.monthAndDay.' . $pref);
     $title       = trans('firefly.report_default', ['start' => $start->formatLocalized($monthFormat), 'end' => $end->formatLocalized($monthFormat)]);
 
diff --git a/config/app.php b/config/app.php
index 93cef6cb6f..ced4a3e0b6 100644
--- a/config/app.php
+++ b/config/app.php
@@ -52,7 +52,7 @@ return [
     |
     */
 
-    'locale'          => 'en',
+    'locale'          => 'en_US',
 
     /*
     |--------------------------------------------------------------------------
@@ -65,7 +65,7 @@ return [
     |
     */
 
-    'fallback_locale' => 'en',
+    'fallback_locale' => 'en_US',
 
     /*
     |--------------------------------------------------------------------------
diff --git a/config/firefly.php b/config/firefly.php
index 0bab3ab71a..ced04e09a9 100644
--- a/config/firefly.php
+++ b/config/firefly.php
@@ -99,12 +99,12 @@ return [
             'Cash account'        => 'cash',
         ],
     'lang'                     => [
-        'en' => 'English',
-        'nl' => 'Nederlands'
+        'en_US' => 'English',
+        'nl_NL' => 'Nederlands'
     ],
     'locales'                  => [
-        'en' => ['en', 'English', 'en_US', 'en_US.utf8'],
-        'nl' => ['nl', 'Dutch', 'nl_NL', 'nl_NL.utf8'],
+        'en_US' => ['en', 'English', 'en_US', 'en_US.utf8'],
+        'nl_NL' => ['nl', 'Dutch', 'nl_NL', 'nl_NL.utf8'],
     ],
     'transactionTypesByWhat'   => [
         'expenses'   => ['Withdrawal'],
@@ -125,12 +125,12 @@ return [
     ],
 
     'month'                    => [
-        'en' => '%B %Y',
-        'nl' => '%B %Y',
+        'en_US' => '%B %Y',
+        'nl_NL' => '%B %Y',
     ],
     'monthAndDay'              => [
-        'en' => '%B %e, %Y',
-        'nl' => '%e %B %Y',
+        'en_US' => '%B %e, %Y',
+        'nl_NL' => '%e %B %Y',
     ],
 
 ];