diff --git a/.gitignore b/.gitignore
index 170c7e2..bbfceca 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ composer.lock
 .php_cs.cache
 _meta
 .serenata
+.vscode
diff --git a/.travis.yml b/.travis.yml
index a6d7fef..a51505b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,3 @@
-sudo: false
 dist: xenial
 language: php
 
@@ -8,9 +7,6 @@ php:
   - 7.3
   - 7.4
 
-matrix:
-  fast_finish: true
-    
 cache:
   directories:
     - $HOME/.composer/cache
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 27f62ce..8bed647 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [4.4.1]
+- Throws an exception if `translate` placeholder are not numeric or array.
+- Fix issue with numeric placeholder with non plural keys. See [userfrosting#1090](https://github.com/userfrosting/UserFrosting/issues/1090#issuecomment-620832985).
+
 ## [4.4.0]
 Complete rewrite of the Translator.
 
@@ -23,7 +27,7 @@ All methods of the `Translator` are the same for backward compatibility. The onl
 - `@PLURAL_RULE` special key removed. Use the Locale configuration file (`locale.yaml`) `plural_rule` attribute instead.
 - Translator can't load multiple locale anymore. Use the Locale configuration file `parents` attribute instead.
 
-See updated [documentation](README.md) for more details on how to use the new Translator, Locale and Dictionary. 
+See updated [documentation](README.md) for more details on how to use the new Translator, Locale and Dictionary.
 
 ## [4.3.0]
 - Dropping support for PHP 5.6 & 7.0
@@ -57,6 +61,7 @@ See updated [documentation](README.md) for more details on how to use the new Tr
 ## 4.0.0
 - Initial release
 
+[4.4.1]: https://github.com/userfrosting/i18n/compare/4.4.0...4.4.1
 [4.4.0]: https://github.com/userfrosting/i18n/compare/4.3.0...4.4.0
 [4.3.0]: https://github.com/userfrosting/i18n/compare/4.2.1...4.3.0
 [4.2.1]: https://github.com/userfrosting/i18n/compare/4.2.0...4.2.1
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 0000000..5c03ad2
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,3 @@
+parameters:
+  level: max
+  treatPhpDocTypesAsCertain: false
\ No newline at end of file
diff --git a/src/Translator.php b/src/Translator.php
index ebb2e60..577df8a 100644
--- a/src/Translator.php
+++ b/src/Translator.php
@@ -79,13 +79,17 @@ public function getLocale(): LocaleInterface
      *
      * Return the $messageKey if not match is found
      *
-     * @param string    $messageKey   The id of the message id to translate. can use dot notation for array
-     * @param array|int $placeholders An optional hash of placeholder names => placeholder values to substitute (default : [])
+     * @param string      $messageKey   The id of the message id to translate. can use dot notation for array
+     * @param mixed[]|int $placeholders An optional hash of placeholder names => placeholder values to substitute (default : [])
      *
      * @return string The translated message.
      */
     public function translate(string $messageKey, $placeholders = []): string
     {
+        if (!is_numeric($placeholders) && !is_array($placeholders)) {
+            throw new \InvalidArgumentException('Placeholders must be array or numeric value.');
+        }
+
         // Get the correct message from the specified key
         $message = $this->getMessageFromKey($messageKey, $placeholders);
 
@@ -100,8 +104,8 @@ public function translate(string $messageKey, $placeholders = []): string
      * Go throught all registered language keys avaiable and find the correct
      * one to use, using the placeholders to select the correct plural form.
      *
-     * @param string    $messageKey   The key to find the message for
-     * @param array|int $placeholders Passed by reference, since plural placeholder will be added for later processing
+     * @param string      $messageKey   The key to find the message for
+     * @param mixed[]|int $placeholders Passed by reference, since plural placeholder will be added for later processing
      *
      * @return string The message string
      */
@@ -176,7 +180,7 @@ protected function getMessageFromKey(string $messageKey, &$placeholders): string
      * Return the plural key from a translation array.
      * If no plural key is defined in the `@PLURAL` instruction of the message array, we fallback to the default one.
      *
-     * @param array $messageArray
+     * @param mixed[] $messageArray
      *
      * @return string
      */
@@ -192,14 +196,14 @@ protected function getPluralKey(array $messageArray): string
     /**
      * Return the plural value, aka the nummber to display, from the placeholder values.
      *
-     * @param array|int $placeholders Placeholder
-     * @param string    $pluralKey    The plural key, for key => value match
+     * @param mixed[]|int $placeholders Placeholder
+     * @param string      $pluralKey    The plural key, for key => value match
      *
      * @return int|null The number, null if not found
      */
     protected function getPluralValue($placeholders, string $pluralKey): ?int
     {
-        if (isset($placeholders[$pluralKey])) {
+        if (is_array($placeholders) && isset($placeholders[$pluralKey])) {
             return (int) $placeholders[$pluralKey];
         }
 
@@ -215,8 +219,8 @@ protected function getPluralValue($placeholders, string $pluralKey): ?int
      * Return the correct plural message form to use.
      * When multiple plural form are available for a message, this method will return the correct oen to use based on the numeric value.
      *
-     * @param array $messageArray The array with all the form inside ($pluralRule => $message)
-     * @param int   $pluralValue  The numeric value used to select the correct message
+     * @param mixed[] $messageArray The array with all the form inside ($pluralRule => $message)
+     * @param int     $pluralValue  The numeric value used to select the correct message
      *
      * @return int|null Returns which key from $messageArray to use
      */
@@ -253,13 +257,18 @@ protected function getPluralMessageKey(array $messageArray, int $pluralValue): ?
      * Parse Placeholder.
      * Replace placeholders in the message with their values from the passed argument.
      *
-     * @param string $message      The message to replace placeholders in
-     * @param array  $placeholders An optional hash of placeholder (names => placeholder) values to substitute (default : [])
+     * @param string      $message      The message to replace placeholders in
+     * @param mixed[]|int $placeholders An optional hash of placeholder (names => placeholder) values to substitute (default : [])
      *
      * @return string The message with replaced placeholders
      */
-    protected function parsePlaceHolders(string $message, array $placeholders): string
+    protected function parsePlaceHolders(string $message, $placeholders): string
     {
+        // If $placeholders is not an array at this point, we make it an array, using `plural` as the key
+        if (!is_array($placeholders)) {
+            $placeholders = [$this->defaultPluralKey => $placeholders];
+        }
+
         // Interpolate translatable placeholders values. This allows to
         // pre-translate placeholder which value starts with the `&` caracter
         foreach ($placeholders as $name => $value) {
@@ -304,15 +313,18 @@ protected function parsePlaceHolders(string $message, array $placeholders): stri
      * @see https://developer.mozilla.org/en-US/docs/Mozilla/Localization/Localization_and_Plurals
      *
      * @param int|float $number    The number we want to get the plural case for. Float numbers are floored.
-     * @param mixed     $forceRule False to use the plural rule of the language package
+     * @param int|bool  $forceRule False to use the plural rule of the language package
      *                             or an integer to force a certain plural rule
      *
      * @return int The plural-case we need to use for the number plural-rule combination
      */
     public function getPluralForm($number, $forceRule = false)
     {
-        // Default to English rule (1) or the forced one
-        $ruleNumber = $this->getPluralRuleNumber($forceRule);
+        if (is_int($forceRule)) {
+            $ruleNumber = $forceRule;
+        } else {
+            $ruleNumber = $this->dictionary->getLocale()->getPluralRule();
+        }
 
         // Get the rule class
         $class = "\UserFrosting\I18n\PluralRules\Rule$ruleNumber";
@@ -322,20 +334,4 @@ public function getPluralForm($number, $forceRule = false)
 
         return $class::getRule((int) $number);
     }
-
-    /**
-     * Return the correct rule number to use.
-     *
-     * @param int|bool $forceRule Force to use a particular rule. Otherwise, use the language defined one
-     *
-     * @return int
-     */
-    protected function getPluralRuleNumber($forceRule): int
-    {
-        if ($forceRule !== false) {
-            return $forceRule;
-        }
-
-        return $this->dictionary->getLocale()->getPluralRule();
-    }
 }
diff --git a/tests/TranslatorTest.php b/tests/TranslatorTest.php
index 9313340..645733a 100644
--- a/tests/TranslatorTest.php
+++ b/tests/TranslatorTest.php
@@ -87,6 +87,15 @@ public function testGetPluralForm(): void
         $this->assertEquals($translator->translate('X_CARS', 2), '2 cars');
     }
 
+    /**
+     * @depends testGetPluralForm
+     */
+    public function testGetPluralFormForced(): void
+    {
+        $translator = $this->getTranslator('en_US');
+        $this->assertSame(1, $translator->getPluralForm(2, 0));
+    }
+
     /**
      * @depends testGetPluralForm
      * Test locale wihtout a plural rule.
@@ -131,6 +140,31 @@ public function testTranslate(string $key, $placeholders, string $expectedResult
         $this->assertEquals($expectedResultFrench, $frenchTranslator->translate($key, $placeholders));
     }
 
+    /**
+     * @depends testTranslate
+     */
+    public function testTranslateKeyWithNoPlural(): void
+    {
+        $translator = $this->getTranslator();
+        $this->assertEquals($translator->translate('USERNAME', 123), 'Username');
+        $this->assertEquals($translator->translate('X_FOO'), 'x foos');
+        $this->assertEquals($translator->translate('X_FOO', ['plural' => 1]), '1x foos');
+        $this->assertEquals($translator->translate('X_FOO', 1), '1x foos');
+        $this->assertEquals($translator->translate('X_FOO', 123), '123x foos');
+    }
+
+    /**
+     * Force test a non-array / non-int placeholder.
+     *
+     * @depends testTranslate
+     */
+    public function testTranslateKeyWithBadPlaceholder(): void
+    {
+        $translator = $this->getTranslator();
+        $this->expectException(\InvalidArgumentException::class);
+        $this->assertEquals($translator->translate('X_FOO', 'xx'), 'xxx foos');
+    }
+
     /**
      * Basic test to see if triple dependency works.
      */
diff --git a/tests/data/sprinkles/core/locale/en_US/test.php b/tests/data/sprinkles/core/locale/en_US/test.php
index 0ca7c8b..6a5b000 100644
--- a/tests/data/sprinkles/core/locale/en_US/test.php
+++ b/tests/data/sprinkles/core/locale/en_US/test.php
@@ -11,6 +11,8 @@
 return [
     'USERNAME' => 'Username',
 
+    'X_FOO' => '{{plural}}x foos',
+
     'BASE_FALLBACK' => 'Base fallback',
 
     'ACCOUNT' => [