First of all, thank you all for your positive attitude, diverse opinions and constructive ideas. I absolutely love the spirit of this community,
Secondly, s are Mexican , not Spanish ! But again (this is serious, I promise), stereotypes are more commonly linked to regional cultures than to languages.
I also consider the visual “feature” of flags a negative UI design — they attract my attention between other equally-important content or topics (in titles, not so much in tags). So I’d consider it a controversial feature.
On the contrary, the option of ISO icons proposed by @Stefan is different because it’s monochrome, like letters. They would assemble and icons. They are region neutral, visual (although it doesn’t catch your attention badly like colorful emojis) and compact. But they can’t be used in tags.
A nice option for tags could be then using localized names for languages, as @_Chris proposed and Wikimedia uses. Wikimedia is an organization known for its multicultural efforts and positive attitude to diversity. But I’ll probably add a
lang: prefix, as in #lang:español, or #lang:dutch or, #lang:euskara, which fit with #dic entries (e.g. #dic:floss) format and make the format mutually coherent, IMO.
This option has a plus too, because with a single CSS rule (
a[href^="/tags/lang:"]) the style can be customized for e.g. to change the color of the lang tags or underline them at once.
TL;DR: My preference will be using ISO icons as title prefixes and “#lang:language” as a tags:
(:lang_en:) This is a topic title written in English
lang:english, those, words, are, tags
(:lang_es:) Este es el título de un hilo escrito en español
lang:español, estas, palabras, son, etiquetas