menu for choose language

[dontsovcmc]

config.toml:
add flag parameter to all languages

[Languages.en.params]
  flag = "🇬🇧"

add code to header.html

        {{ if .Site.IsMultiLingual }}
        <ul class="navbar-nav ml-auto language-list">
            {{ $pageLang := .Page.Lang}}
            {{ range .Site.Home.AllTranslations }}
            {{ if ne $pageLang .Lang }}
            <li class="nav-item">
              <a class="nav-link scroll-to" href="{{ .Permalink }}">
                {{ .Site.Params.flag }}
              </a>
            </li>
            {{ end }}
            {{ end }}
        </ul>
        {{ end }}

[ChrisySuisse]

Additionally this is helpful:
https://discourse.gohugo.io/t/access-multilingual-data-in-partials/46189/5