diff --git a/packages/trevas/package.json b/packages/trevas/package.json
index 37466d89..c3a45da2 100644
--- a/packages/trevas/package.json
+++ b/packages/trevas/package.json
@@ -30,4 +30,4 @@
 		"data-forge": "^1.8.8",
 		"date-fns": "^2.27.0"
 	}
-}
+}
\ No newline at end of file
diff --git a/packages/trevas/src/tests/interpretors/arithmetic.spec.js b/packages/trevas/src/tests/interpretors/arithmetic.spec.js
index bd840d98..397322ef 100644
--- a/packages/trevas/src/tests/interpretors/arithmetic.spec.js
+++ b/packages/trevas/src/tests/interpretors/arithmetic.spec.js
@@ -214,4 +214,11 @@ describe('arithmetic', () => {
 			).toEqual(2);
 		});
 	});
+	describe('issues', () => {
+		it('#134', () => {
+			// currently stops at `10`, probably considering `-9` as another integer, dropping it
+			// commenting that for now because we know it is a VTL spec problem not an implementation one
+			//expect(interpret('10 -9')).toEqual(1);
+		});
+	});
 });
diff --git a/packages/trevas/src/tests/interpretors/functions/cast.spec.js b/packages/trevas/src/tests/interpretors/functions/cast.spec.js
index d87ce2d9..dee38d62 100644
--- a/packages/trevas/src/tests/interpretors/functions/cast.spec.js
+++ b/packages/trevas/src/tests/interpretors/functions/cast.spec.js
@@ -123,28 +123,28 @@ describe('cast', () => {
 		});
 	});
 	describe('time', () => {
-		it('cast time into integer', () => {});
-		it('cast time into number', () => {});
-		it('cast time into boolean', () => {});
-		it('cast time into time', () => {});
-		it('cast time into date', () => {});
-		it('cast time into time_period', () => {});
-		it('cast time into string', () => {});
-		it('cast time into duration', () => {});
+		it('cast time into integer', () => { });
+		it('cast time into number', () => { });
+		it('cast time into boolean', () => { });
+		it('cast time into time', () => { });
+		it('cast time into date', () => { });
+		it('cast time into time_period', () => { });
+		it('cast time into string', () => { });
+		it('cast time into duration', () => { });
 	});
 	describe('date', () => {
 		// There's no date literal. We use a first cast to define the date.
 		const aDate = interpretVar('cast("1998-07-12", date, "YYYY-MM-DD")', {});
-		it('cast date into integer', () => {});
-		it('cast date into number', () => {});
-		it('cast date into boolean', () => {});
-		it('cast date into time', () => {});
+		it('cast date into integer', () => { });
+		it('cast date into number', () => { });
+		it('cast date into boolean', () => { });
+		it('cast date into time', () => { });
 		it('cast date into date', () => {
 			expect(interpret('cast(aDate, date, "YYYY-MM")', { aDate })).toEqual(
 				interpret('cast("1998-07-12", date, "YYYY-MM")', {})
 			);
 		});
-		it('cast date into time_period', () => {});
+		it('cast date into time_period', () => { });
 		it('cast date into string', () => {
 			expect(interpret('cast(aDate, string, "YYYY-DD-MM")', { aDate })).toEqual(
 				'1998-12-07'
@@ -156,17 +156,26 @@ describe('cast', () => {
 			// 	'1998-12-31'
 			// );
 		});
-		it('cast date into duration', () => {});
+		it('cast date into duration', () => { });
+		it("cast date to string with localization", () => {
+			navigatorLanguageSpy = jest.spyOn(Object.getPrototypeOf(navigator), 'language', 'get');
+			expect(interpret('cast(aDate, string, "MMMM")', { aDate })).toEqual("July");
+			navigatorLanguageSpy.mockReturnValue("fr");
+			expect(interpret('cast(aDate, string, "MMMM")', { aDate })).toEqual("juillet");
+			navigatorLanguageSpy.mockReturnValue("es");
+			expect(interpret('cast(aDate, string, "MMMM")', { aDate })).toEqual("July");
+			navigatorLanguageSpy.mockRestore();
+		});
 	});
 	describe('time_period', () => {
-		it('cast time_period into integer', () => {});
-		it('cast time_period into number', () => {});
-		it('cast time_period into boolean', () => {});
-		it('cast time_period into time', () => {});
-		it('cast time_period into date', () => {});
-		it('cast time_period into time_period', () => {});
-		it('cast time_period into string', () => {});
-		it('cast time_period into duration', () => {});
+		it('cast time_period into integer', () => { });
+		it('cast time_period into number', () => { });
+		it('cast time_period into boolean', () => { });
+		it('cast time_period into time', () => { });
+		it('cast time_period into date', () => { });
+		it('cast time_period into time_period', () => { });
+		it('cast time_period into string', () => { });
+		it('cast time_period into duration', () => { });
 	});
 	describe('string', () => {
 		it('cast string into integer', () => {
@@ -186,7 +195,7 @@ describe('cast', () => {
 				CastTypeError
 			);
 		});
-		it('cast string into time', () => {});
+		it('cast string into time', () => { });
 		it('should cast string into date', () => {
 			expect(interpret('cast("1998-07-12", date, "YYYY-MM-DD")', {})).toEqual(
 				'1998-07-12'
@@ -195,11 +204,11 @@ describe('cast', () => {
 				'1998-07-12'
 			);
 		});
-		it('cast string into time_period', () => {});
+		it('cast string into time_period', () => { });
 		it('cast string into string', () => {
 			expect(interpret('cast("aaa", string)', {})).toEqual('aaa');
 		});
-		it('cast string into duration', () => {});
+		it('cast string into duration', () => { });
 		const dsI = {
 			dataStructure: { col_1: {}, col_2: {} },
 			dataPoints: { col_1: ['1', '2', '3'], col_2: ['-1', null, null] },
@@ -224,13 +233,13 @@ describe('cast', () => {
 		});
 	});
 	describe('duration', () => {
-		it('cast duration into integer', () => {});
-		it('cast duration into number', () => {});
-		it('cast duration into boolean', () => {});
-		it('cast duration into time', () => {});
-		it('cast duration into date', () => {});
-		it('cast duration into time_period', () => {});
-		it('cast duration into string', () => {});
-		it('cast duration into duration', () => {});
+		it('cast duration into integer', () => { });
+		it('cast duration into number', () => { });
+		it('cast duration into boolean', () => { });
+		it('cast duration into time', () => { });
+		it('cast duration into date', () => { });
+		it('cast duration into time_period', () => { });
+		it('cast duration into string', () => { });
+		it('cast duration into duration', () => { });
 	});
 });
diff --git a/packages/trevas/src/tests/utils/dates.spec.js b/packages/trevas/src/tests/utils/dates.spec.js
new file mode 100644
index 00000000..59ded290
--- /dev/null
+++ b/packages/trevas/src/tests/utils/dates.spec.js
@@ -0,0 +1,26 @@
+import { fromNavLangToLocale } from '../../utils';
+
+describe("dates utils functions", () => {
+    let navigatorLanguageSpy;
+
+    beforeEach(() => {
+        navigatorLanguageSpy = jest.spyOn(Object.getPrototypeOf(navigator), 'language', 'get');
+    });
+
+    it("handles default localization", () => {
+        // navigator.language is `en-US` by default
+        let locale = fromNavLangToLocale();
+        expect(locale.code).toEqual("en-US");
+    });
+
+    it("handles french localization", () => {
+        navigatorLanguageSpy.mockReturnValue("fr");
+        let locale = fromNavLangToLocale();
+        expect(locale.code).toEqual("fr")
+    });
+
+
+    afterEach(() => {
+        navigatorLanguageSpy.mockRestore();
+    });
+});
\ No newline at end of file
diff --git a/packages/trevas/src/utils/dates.js b/packages/trevas/src/utils/dates.js
index deef4f68..b0e2487f 100644
--- a/packages/trevas/src/utils/dates.js
+++ b/packages/trevas/src/utils/dates.js
@@ -1,4 +1,14 @@
 import { format } from 'date-fns';
+import { fr, enUS } from "date-fns/locale";
+
+export const fromNavLangToLocale = () => {
+	switch (navigator.language) {
+		case "fr":
+			return fr
+		default:
+			return enUS
+	}
+};
 
 export const getCurrentDate = () => new Date();
 
@@ -10,5 +20,5 @@ export const getDate = (dateStr, mask) =>
 
 export const getStringFromDate = (date, mask) =>
 	mask
-		? format(new Date(`${date}`), buildDateFnsMask(mask))
+		? format(new Date(`${date}`), buildDateFnsMask(mask), { locale: fromNavLangToLocale() })
 		: new Date(`${date}`);
diff --git a/packages/trevas/src/utils/index.js b/packages/trevas/src/utils/index.js
index e7b5186d..cca85443 100644
--- a/packages/trevas/src/utils/index.js
+++ b/packages/trevas/src/utils/index.js
@@ -1,6 +1,6 @@
 export { replaceConstantType } from './constants';
 export { getTokenType } from './context';
-export { getDate, getStringFromDate, getCurrentDate } from './dates';
+export { getDate, getStringFromDate, getCurrentDate, fromNavLangToLocale } from './dates';
 export { getTokenName } from './parser';
 export * from './datasets';
 export * from './null';