diff --git a/system/HTTP/Negotiate.php b/system/HTTP/Negotiate.php
index 6ac2d06b7bc4..74aa4706227d 100644
--- a/system/HTTP/Negotiate.php
+++ b/system/HTTP/Negotiate.php
@@ -179,7 +179,7 @@ public function encoding(array $supported = []): string
 	 */
 	public function language(array $supported): string
 	{
-		return $this->getBestMatch($supported, $this->request->getHeaderLine('accept-language'));
+		return $this->getBestMatch($supported, $this->request->getHeaderLine('accept-language'), false, false, true);
 	}
 
 	//--------------------------------------------------------------------
@@ -198,10 +198,11 @@ public function language(array $supported): string
 	 * @param boolean $enforceTypes If TRUE, will compare media types and sub-types.
 	 * @param boolean $strictMatch  If TRUE, will return empty string on no match.
 	 *                              If FALSE, will return the first supported element.
+	 * @param boolean $matchLocales If TRUE, will match locale sub-types to a broad type (fr-FR = fr)
 	 *
 	 * @return string Best match
 	 */
-	protected function getBestMatch(array $supported, string $header = null, bool $enforceTypes = false, bool $strictMatch = false): string
+	protected function getBestMatch(array $supported, string $header = null, bool $enforceTypes = false, bool $strictMatch = false, bool $matchLocales = false): string
 	{
 		if (empty($supported))
 		{
@@ -232,7 +233,7 @@ protected function getBestMatch(array $supported, string $header = null, bool $e
 			// If an acceptable value is supported, return it
 			foreach ($supported as $available)
 			{
-				if ($this->match($accept, $available, $enforceTypes))
+				if ($this->match($accept, $available, $enforceTypes, $matchLocales))
 				{
 					return $available;
 				}
@@ -337,12 +338,14 @@ public function parseHeader(string $header): array
 	/**
 	 * Match-maker
 	 *
-	 * @param  array   $acceptable
-	 * @param  string  $supported
-	 * @param  boolean $enforceTypes
+	 * @param array   $acceptable
+	 * @param string  $supported
+	 * @param boolean $enforceTypes
+	 * @param boolean $matchLocales
+	 *
 	 * @return boolean
 	 */
-	protected function match(array $acceptable, string $supported, bool $enforceTypes = false): bool
+	protected function match(array $acceptable, string $supported, bool $enforceTypes = false, $matchLocales = false): bool
 	{
 		$supported = $this->parseHeader($supported);
 		if (is_array($supported) && count($supported) === 1)
@@ -363,6 +366,12 @@ protected function match(array $acceptable, string $supported, bool $enforceType
 			return $this->matchTypes($acceptable, $supported);
 		}
 
+		// Do we need to match locales against broader locales?
+		if ($matchLocales)
+		{
+			return $this->matchLocales($acceptable, $supported);
+		}
+
 		return false;
 	}
 
@@ -409,8 +418,14 @@ protected function matchParameters(array $acceptable, array $supported): bool
 	 */
 	public function matchTypes(array $acceptable, array $supported): bool
 	{
-		list($aType, $aSubType) = explode('/', $acceptable['value']);
-		list($sType, $sSubType) = explode('/', $supported['value']);
+		[
+			$aType,
+			$aSubType,
+		] = explode('/', $acceptable['value']);
+		[
+			$sType,
+			$sSubType,
+		] = explode('/', $supported['value']);
 
 		// If the types don't match, we're done.
 		if ($aType !== $sType)
@@ -429,4 +444,25 @@ public function matchTypes(array $acceptable, array $supported): bool
 	}
 
 	//--------------------------------------------------------------------
+
+	/**
+	 * Will match locales against their broader pairs, so that fr-FR would
+	 * match a supported localed of fr
+	 *
+	 * @param array $acceptable
+	 * @param array $supported
+	 *
+	 * @return boolean
+	 */
+	public function matchLocales(array $acceptable, array $supported): bool
+	{
+		$aBroad = mb_strpos($acceptable['value'], '-') > 0
+			? mb_substr($acceptable['value'], 0, mb_strpos($acceptable['value'], '-'))
+			: $acceptable['value'];
+		$sBroad = mb_strpos($supported['value'], '-') > 0
+			? mb_substr($supported['value'], 0, mb_strpos($supported['value'], '-'))
+			: $supported['value'];
+
+		return strtolower($aBroad) === strtolower($sBroad);
+	}
 }
diff --git a/tests/system/HTTP/IncomingRequestTest.php b/tests/system/HTTP/IncomingRequestTest.php
index 6457f92da6a6..ef1b4f6a8de1 100644
--- a/tests/system/HTTP/IncomingRequestTest.php
+++ b/tests/system/HTTP/IncomingRequestTest.php
@@ -202,22 +202,43 @@ public function testSetBadLocale()
 
 	//--------------------------------------------------------------------
 
+	/**
+	 * @see https://github.com/codeigniter4/CodeIgniter4/issues/2774
+	 */
 	public function testNegotiatesLocale()
 	{
-		$_SERVER['HTTP_ACCEPT_LANGUAGE'] = 'es; q=1.0, en; q=0.5';
+		$_SERVER['HTTP_ACCEPT_LANGUAGE'] = 'fr-FR; q=1.0, en; q=0.5';
 
 		$config                   = new App();
 		$config->negotiateLocale  = true;
 		$config->supportedLocales = [
+			'fr',
 			'en',
-			'es',
 		];
 		$config->baseURL          = 'http://example.com';
 
 		$request = new IncomingRequest($config, new URI(), null, new UserAgent());
 
 		$this->assertEquals($config->defaultLocale, $request->getDefaultLocale());
-		$this->assertEquals('es', $request->getLocale());
+		$this->assertEquals('fr', $request->getLocale());
+	}
+
+	public function testNegotiatesLocaleOnlyBroad()
+	{
+		$_SERVER['HTTP_ACCEPT_LANGUAGE'] = 'fr; q=1.0, en; q=0.5';
+
+		$config                   = new App();
+		$config->negotiateLocale  = true;
+		$config->supportedLocales = [
+			'fr',
+			'en',
+		];
+		$config->baseURL          = 'http://example.com';
+
+		$request = new IncomingRequest($config, new URI(), null, new UserAgent());
+
+		$this->assertEquals($config->defaultLocale, $request->getDefaultLocale());
+		$this->assertEquals('fr', $request->getLocale());
 	}
 
 	// The negotiation tests below are not intended to exercise the HTTP\Negotiate class -
diff --git a/tests/system/HTTP/NegotiateTest.php b/tests/system/HTTP/NegotiateTest.php
index 1c8ffb204f3c..1db5cdae4cbd 100644
--- a/tests/system/HTTP/NegotiateTest.php
+++ b/tests/system/HTTP/NegotiateTest.php
@@ -138,6 +138,17 @@ public function testAcceptLanguageBasics()
 	}
 
 	//--------------------------------------------------------------------
+
+	/**
+	 * @see https://github.com/codeigniter4/CodeIgniter4/issues/2774
+	 */
+	public function testAcceptLanguageMatchesBroadly()
+	{
+		$this->request->setHeader('Accept-Language', 'fr-FR,fr;q=0.9,en-US;q=0.8,en;q=0.7');
+
+		$this->assertEquals('fr', $this->negotiate->language(['fr', 'en']));
+	}
+
 	public function testBestMatchEmpty()
 	{
 		$this->expectException(Exceptions\HTTPException::class);