mkdocs-material/material/partials/language.html

{% set languages = config.extra.language | default("en") %}
{% if languages is string %}
  {% set languages = languages.split(",") | map("trim") %}
{% endif %}
{% import "partials/language/" + (languages | first) + ".html" as lang %}
{% macro t(key) %}{{ {
  "search.languages": languages | join(", ")
}[key] or lang.t(key) }}{% endmacro %}