diff --git a/samples/Basic/43_Merge_workbooks.php b/samples/Basic/43_Merge_workbooks.php
index 86314b3ba3..28353cc60b 100644
--- a/samples/Basic/43_Merge_workbooks.php
+++ b/samples/Basic/43_Merge_workbooks.php
@@ -18,6 +18,10 @@
 
 foreach ($spreadsheet2->getSheetNames() as $sheetName) {
     $sheet = $spreadsheet2->getSheetByName($sheetName);
+    if ($sheet === null) {
+        continue;
+    }
+
     $sheet->setTitle($sheet->getTitle() . ' copied');
     $spreadsheet1->addExternalSheet($sheet);
 }
diff --git a/tests/PhpSpreadsheetTests/Calculation/TranslationTest.php b/tests/PhpSpreadsheetTests/Calculation/TranslationTest.php
new file mode 100644
index 0000000000..1eb66a0a1c
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/TranslationTest.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Settings;
+use PHPUnit\Framework\TestCase;
+
+class TranslationTest extends TestCase
+{
+    private $compatibilityMode;
+
+    private $returnDate;
+
+    protected function setUp(): void
+    {
+        $this->compatibilityMode = Functions::getCompatibilityMode();
+        $this->returnDate = Functions::getReturnDateType();
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_EXCEL);
+        Functions::setReturnDateType(Functions::RETURNDATE_EXCEL);
+    }
+
+    protected function tearDown(): void
+    {
+        Functions::setCompatibilityMode($this->compatibilityMode);
+        Functions::setReturnDateType($this->returnDate);
+    }
+
+    /**
+     * @dataProvider providerTranslations
+     */
+    public function testTranslation(string $expectedResult, string $locale, string $formula): void
+    {
+        $validLocale = Settings::setLocale($locale);
+        if (!$validLocale) {
+            self::markTestSkipped("Unable to set locale to {$locale}");
+        }
+
+        $translatedFormula = Calculation::getInstance()->_translateFormulaToLocale($formula);
+        self::assertSame($expectedResult, $translatedFormula);
+
+        $restoredFormula = Calculation::getInstance()->_translateFormulaToEnglish($translatedFormula);
+        self::assertSame($formula, $restoredFormula);
+    }
+
+    public function providerTranslations()
+    {
+        return require 'tests/data/Calculation/Translations.php';
+    }
+}
diff --git a/tests/data/Calculation/Translations.php b/tests/data/Calculation/Translations.php
new file mode 100644
index 0000000000..d470a05cb2
--- /dev/null
+++ b/tests/data/Calculation/Translations.php
@@ -0,0 +1,48 @@
+<?php
+
+return [
+    [
+        '=DAGEN360(DATUM(2010;2;5);DATUM(2010;12;31);WAAR)',
+        'nl',
+        '=DAYS360(DATE(2010,2,5),DATE(2010,12,31),TRUE)',
+    ],
+    [
+        '=DIAS360(DATA(2010;2;5);DATA(2010;12;31);VERDADEIRO)',
+        'pt_br',
+        '=DAYS360(DATE(2010,2,5),DATE(2010,12,31),TRUE)',
+    ],
+    [
+        '=ДНЕЙ360(ДАТА(2010;2;5);ДАТА(2010;12;31);ИСТИНА)',
+        'ru',
+        '=DAYS360(DATE(2010,2,5),DATE(2010,12,31),TRUE)',
+    ],
+    [
+        '=TEKST.SAMENVOEGEN(A1; " "; B1)',
+        'nl',
+        '=CONCATENATE(A1, " ", B1)',
+    ],
+    [
+        '=TEKST.SAMENVOEGEN("""Hello "; B1; ""","; " I said.")',
+        'nl',
+        '=CONCATENATE("""Hello ", B1, """,", " I said.")',
+    ],
+    [
+        '=TEKST.SAMENVOEGEN(JAAR(VANDAAG());
+            " is ";
+            ALS(
+                DAYS(DATUM(JAAR(VANDAAG())+1; 1; 1); DATUM(JAAR(VANDAAG()); 1; 1)) = 365;
+                "NOT a Leap Year";
+                "a Leap Year"
+            )
+        )',
+        'nl',
+        '=CONCATENATE(YEAR(TODAY()),
+            " is ",
+            IF(
+                DAYS(DATE(YEAR(TODAY())+1, 1, 1), DATE(YEAR(TODAY()), 1, 1)) = 365,
+                "NOT a Leap Year",
+                "a Leap Year"
+            )
+        )',
+    ],
+];