diff --git a/src/objects/LinkObject.php b/src/objects/LinkObject.php
index 1eab36d..837875e 100644
--- a/src/objects/LinkObject.php
+++ b/src/objects/LinkObject.php
@@ -11,6 +11,16 @@ class LinkObject implements ObjectInterface {
 	
 	/** @var string */
 	protected $href;
+	/** @var string */
+	protected $rel;
+	/** @var LinkObject */
+	protected $describedby;
+	/** @var string */
+	protected $title;
+	/** @var string */
+	protected $type;
+	/** @var string[] */
+	protected $hreflang = [];
 	/** @var MetaObject */
 	protected $meta;
 	
@@ -31,6 +41,25 @@ public function __construct($href=null, array $meta=[]) {
 	 * human api
 	 */
 	
+	/**
+	 * @param string $href
+	 */
+	public function setDescribedBy($href) {
+		$this->setDescribedByLinkObject(new LinkObject($href));
+	}
+	
+	/**
+	 * @param string $language
+	 */
+	public function addLanguage($language) {
+		if ($this->hreflang === []) {
+			$this->setHreflang($language);
+		}
+		else {
+			$this->setHreflang(...array_merge($this->hreflang, [$language]));
+		}
+	}
+	
 	/**
 	 * @param string $key
 	 * @param mixed  $value
@@ -54,6 +83,45 @@ public function setHref($href) {
 		$this->href = $href;
 	}
 	
+	/**
+	 * @todo validate according to https://tools.ietf.org/html/rfc8288#section-2.1
+	 * 
+	 * @param string $relationType
+	 */
+	public function setRelationType($relationType) {
+		$this->rel = $relationType;
+	}
+	
+	/**
+	 * @param LinkObject $describedBy
+	 */
+	public function setDescribedByLinkObject(LinkObject $describedBy) {
+		$this->describedby = $describedBy;
+	}
+	
+	/**
+	 * @param string $friendlyTitle
+	 */
+	public function setHumanTitle($humanTitle) {
+		$this->title = $humanTitle;
+	}
+	
+	/**
+	 * @param string $mediaType
+	 */
+	public function setMediaType($mediaType) {
+		$this->type = $mediaType;
+	}
+	
+	/**
+	 * @todo validate according to https://tools.ietf.org/html/rfc5646
+	 * 
+	 * @param string ...$hreflang
+	 */
+	public function setHreflang(...$hreflang) {
+		$this->hreflang = $hreflang;
+	}
+	
 	/**
 	 * @param MetaObject $metaObject
 	 */
@@ -72,6 +140,21 @@ public function isEmpty() {
 		if ($this->href !== null) {
 			return false;
 		}
+		if ($this->rel !== null) {
+			return false;
+		}
+		if ($this->title !== null) {
+			return false;
+		}
+		if ($this->type !== null) {
+			return false;
+		}
+		if ($this->hreflang !== []) {
+			return false;
+		}
+		if ($this->describedby !== null && $this->describedby->isEmpty() === false) {
+			return false;
+		}
 		if ($this->meta !== null && $this->meta->isEmpty() === false) {
 			return false;
 		}
@@ -90,6 +173,26 @@ public function toArray() {
 		
 		$array['href'] = $this->href;
 		
+		if ($this->rel !== null) {
+			$array['rel'] = $this->rel;
+		}
+		if ($this->title !== null) {
+			$array['title'] = $this->title;
+		}
+		if ($this->type !== null) {
+			$array['type'] = $this->type;
+		}
+		if ($this->hreflang !== []) {
+			if (count($this->hreflang) === 1) {
+				$array['hreflang'] = $this->hreflang[0];
+			}
+			else {
+				$array['hreflang'] = $this->hreflang;
+			}
+		}
+		if ($this->describedby !== null && $this->describedby->isEmpty() === false) {
+			$array['describedby'] = $this->describedby->toArray();
+		}
 		if ($this->meta !== null && $this->meta->isEmpty() === false) {
 			$array['meta'] = $this->meta->toArray();
 		}
diff --git a/tests/objects/LinkObjectTest.php b/tests/objects/LinkObjectTest.php
index bdf7e89..ad41068 100644
--- a/tests/objects/LinkObjectTest.php
+++ b/tests/objects/LinkObjectTest.php
@@ -6,6 +6,49 @@
 use PHPUnit\Framework\TestCase;
 
 class LinkObjectTest extends TestCase {
+	public function testSetDescribedBy_HappyPath() {
+		$linkObject = new LinkObject();
+		
+		$this->assertTrue($linkObject->isEmpty());
+		
+		$linkObject->setDescribedBy('https://jsonapi.org');
+		
+		$this->assertFalse($linkObject->isEmpty());
+		
+		$array = $linkObject->toArray();
+		
+		$this->assertArrayHasKey('describedby', $array);
+		$this->assertArrayHasKey('href', $array['describedby']);
+		$this->assertSame('https://jsonapi.org', $array['describedby']['href']);
+	}
+	
+	public function testAddLanguage_HappyPath() {
+		$linkObject = new LinkObject();
+		
+		$this->assertTrue($linkObject->isEmpty());
+		
+		$linkObject->addLanguage('nl-NL');
+		
+		$this->assertFalse($linkObject->isEmpty());
+		
+		$array = $linkObject->toArray();
+		
+		$this->assertArrayHasKey('hreflang', $array);
+		$this->assertSame('nl-NL', $array['hreflang']);
+	}
+	
+	public function testAddLanguage_Multiple() {
+		$linkObject = new LinkObject();
+		
+		$linkObject->addLanguage('nl-NL');
+		$array = $linkObject->toArray();
+		$this->assertSame('nl-NL', $array['hreflang']);
+		
+		$linkObject->addLanguage('en-US');
+		$array = $linkObject->toArray();
+		$this->assertSame(['nl-NL', 'en-US'], $array['hreflang']);
+	}
+	
 	public function testAddMeta_HappyPath() {
 		$linkObject = new LinkObject();
 		
@@ -22,6 +65,83 @@ public function testAddMeta_HappyPath() {
 		$this->assertSame('bar', $array['meta']['foo']);
 	}
 	
+	public function testSetRelationType_HappyPath() {
+		$linkObject = new LinkObject();
+		
+		$this->assertTrue($linkObject->isEmpty());
+		
+		$linkObject->setRelationType('external');
+		
+		$this->assertFalse($linkObject->isEmpty());
+		
+		$array = $linkObject->toArray();
+		
+		$this->assertArrayHasKey('rel', $array);
+		$this->assertSame('external', $array['rel']);
+	}
+	
+	public function testSetDescribedByLinkObject_HappyPath() {
+		$linkObject = new LinkObject();
+		
+		$this->assertTrue($linkObject->isEmpty());
+		
+		$describedBy = new LinkObject('https://jsonapi.org');
+		$linkObject->setDescribedByLinkObject($describedBy);
+		
+		$this->assertFalse($linkObject->isEmpty());
+		
+		$array = $linkObject->toArray();
+		
+		$this->assertArrayHasKey('describedby', $array);
+		$this->assertArrayHasKey('href', $array['describedby']);
+		$this->assertSame('https://jsonapi.org', $array['describedby']['href']);
+	}
+	
+	public function testSetHumanTitle_HappyPath() {
+		$linkObject = new LinkObject();
+		
+		$this->assertTrue($linkObject->isEmpty());
+		
+		$linkObject->setHumanTitle('A link');
+		
+		$this->assertFalse($linkObject->isEmpty());
+		
+		$array = $linkObject->toArray();
+		
+		$this->assertArrayHasKey('title', $array);
+		$this->assertSame('A link', $array['title']);
+	}
+	
+	public function testSetMediaType_HappyPath() {
+		$linkObject = new LinkObject();
+		
+		$this->assertTrue($linkObject->isEmpty());
+		
+		$linkObject->setMediaType('text/html');
+		
+		$this->assertFalse($linkObject->isEmpty());
+		
+		$array = $linkObject->toArray();
+		
+		$this->assertArrayHasKey('type', $array);
+		$this->assertSame('text/html', $array['type']);
+	}
+	
+	public function testSetHreflang_HappyPath() {
+		$linkObject = new LinkObject();
+		
+		$this->assertTrue($linkObject->isEmpty());
+		
+		$linkObject->setHreflang('nl-NL', 'en-US');
+		
+		$this->assertFalse($linkObject->isEmpty());
+		
+		$array = $linkObject->toArray();
+		
+		$this->assertArrayHasKey('hreflang', $array);
+		$this->assertSame(['nl-NL', 'en-US'], $array['hreflang']);
+	}
+	
 	public function testIsEmpty_WithAtMembers() {
 		$linkObject = new LinkObject();