Language learning subreddits

Learn Arabic: questions and practice.

Learn Chinese: questions and practice.

Learn Chinese: Mandarin questions, practice, and resources.

Constructed languages and how to make them.

Words and phrases that don't translate into English.

Learning languages with Duolingo.

The Esperanto language.

Where words come from.

Learn French: grammar, vocabulary, and practice.

The Irish language (Gaeilge).

Practise German with others.

Grammar questions answered.

Learn Japanese: grammar, kanji, and practice.

Learn Korean: grammar, vocabulary, and practice.

Language and linguistics.

Learning languages: methods, resources, and motivation.

Learning Latin: grammar, translation, and texts.

Learning a new language.

Learn Japanese: resources and practice.

Learn Spanish: resources and practice.

Linguistics: the science of language.

Interesting and unusual words.

The constructed language Lojban.

Learning the Russian language.

Learn Russian with lessons and practice.

Learn Spanish: grammar questions, practice, and resources.

Ask for translations between languages.

Building your vocabulary.