Simple language menu in TYPO3

constants.typoscript

// Available language ids
AVAILABLELANGUAGEIDS = 0,1,2,3

LanguageMenu.html

<f:if condition="{menuLanguage}">
	<nav class="c-languageselect">
		<button class="c-languageselect__button" id="languageselectbutton">
			{site.languages.{data.sys_language_uid}.navigationTitle}
			<i class="icon icon-expand_more"></i>
		</button>
		<ul id="languageselect__list" class="c-languageselect__list">
			<f:for each="{menuLanguage}" as="item">
				<li class="c-languageselect__item">
					<f:if condition="{item.active} == 0">
						<f:if condition="{item.available} == 1">
							<f:then>
								<f:link.page class="c-languageselect__link" addQueryString="1" addQueryStringMethod="GET" additionalParams="{L:item.languageUid}">
									{site.languages.{item.languageUid}.navigationTitle}
								</f:link.page>
							</f:then>
							<f:else>
								<span class="c-languageselect__link c-languageselect__link--unavailable">
									{site.languages.{item.languageUid}.navigationTitle}
								</span>
							</f:else>
						</f:if>
					</f:if>
				</li>
			</f:for>
		</ul>
	</nav>
</f:if>

template.typoscript

page = PAGE                                                              
page {                                                                                                                             
                                                                         
	10 = FLUIDTEMPLATE                                                     
	10 {                                                                                                                                      
                                                                         
		dataProcessing {                                                     
                                                                         
			10 = TYPO3\CMS\Frontend\DataProcessing\SiteProcessor               
			10 {                                                               
				as = site                                                        
			}                                                                  
                                                                         
			20 = TYPO3\CMS\Frontend\DataProcessing\MenuProcessor               
			20 {                                                               
				special = language                                               
				special.value = {$AVAILABLELANGUAGEIDS}                          
				as = menuLanguage                                                
			}                                                                  
		}                                                                    
	}                                                                      
}                                                                        
                                                                         

Where does the site.languages object come from?

Aha, from the SiteProcessor

Aha, from the SiteProcessor

Correct. I made one more adjustment, because there was still a bug in the code.