fediversity.eu/themes/hugoplate/layouts/partials/components/language-switcher.html

<!-- Language List -->
{{ $class := .Class }} {{ $context := .Context }} {{ $pageLang := $context.Lang
}} {{ $base:= urls.Parse site.Home.Permalink }} {{ $siteLanguages :=
site.Home.AllTranslations }} {{ $pageLink := replace (replace
$context.RelPermalink (add $pageLang "/") "") $base.Path "/" }} {{ if
$context.IsTranslated }}
<select class="{{ $class }}" onchange="location = this.value">
  {{ range $siteLanguages }} {{ if eq (string $pageLang) (string .Language) }}
  <option
    id="{{ .Language }}"
    value="{{ replace (add .RelPermalink $pageLink) `//` `/` }}"
    selected
  >
    {{ .Language.LanguageName }}
  </option>
  {{ else }}
  <option
    id="{{ .Language }}"
    value="{{ replace (add .RelPermalink $pageLink) `//` `/` }}"
  >
    {{ .Language.LanguageName }}
  </option>
  {{ end }} {{ end }}
</select>
{{ end }}