2000+ Best Resources to Learn
Any Language Online for Free

Anki

Hands down the best flashcards program, based on the spaced repetition alghorithm (which effectiveness is scientifically proven). It has all the options the other programs have (Quizlet, Memrise etc.) and more + hundreds of plugins. It may be quite difficult at the beginning though, so better find some guide (I've written one but it's in Polish). I could write an entire serenade here, just go check it out.

http://italki.com

Find a 1-on-1 online language teacher. Over 100+ languages. Also has a language community to find language resources and get help from native speakers.

Language Transfer

It's run by ONE MAN named Mihalis who is a Cypriot from the UK living in South America. The whole course and all the materials are free. Super helpful, and on all platforms - YouTube, soundcloud, and everything is downloadable to your computer via mp3 file.

Clozemaster

A site where you can learn vocabulary in context by filling close delections in sentences. 65 languages to choose from.

Duolingo

Doesn't need an introduction. The most popular language app in the world.

Mango Languages

Language courses, including some rare languages (Tuvan <3), regional varietes (Latin American Spanish) and specialty courses (e.g. German slang or Shakespearean English).

Forvo

Here you can check the pronunciation of a word in any language, recorded by a native speaker.

Lingq

"This is a subscription service. The free version is extremely limited. But it is one of the best general resources available. Excellent at intermediate or above, but still good for beginners."

Lingbe

Mobile app to find instant language practice. You can hit a button and start practicing a foreign language immediately. You get credits by helping people with your language. Also clubhouse like features for listening to live foreign language conversations.

Radio Lingua

Coffee Break podcasts for language learners. 7 languages, 2000 lessons.

Xefjord

Free Anki courses for 69 different languages.

Radio Garden

You can spin the Earth around and choose Radio stations from all over the world here!

https://cooljugator.com

Verb conjugator, available for 40+ languages

Wikibooks Languages

The books in this subject area deal with languages, in particular foreign language learning. Includes some courses directly on the site.

Norsk Experiment

An interesting experiment - the guy has learnt Norwegian without any dictionaries, without any resources in languages other than Norwegian, he didn't even make any notes or try to remember anything. After two months he was able to read and understand a book in Norwegian. You can read how his full account here.

HiNative

A site similar to aforementioned Lang8. You can ask natives questions about their language and culture, let them assert and correct your pronunciation, ask what is the difference between two words and more. There's also a mobile app.

The Yojiik Website

Free courses and lots of resources developed by The Foreign Service Institute (FSI), an United States federal government's primary training institution for employees of the U.S. foreign affairs community. 48 languages, over 600 courses in public domain.

Language sandwich

A list of foreign YouTube vloggers - 12 different languages.

Busuu

Not as gamified as Duo. Has free version.

InterPals

Language exchange site.

LinGo

A free and open source language acquisition tool with 150+ languages.

Lyricstranslate

More than 1 million translations and transcriptions of song lyrics

GLOSS

41 languages covered, including a number of Arabic varieties. You can choose your level of profficiency, the skill you want to improve (reading, listening), the topic and the competence. There are HUNDREDS of lessons with audio for each language listed.

Advanced Placement

It is a YouTube channel that has many resources for tons of AP topics. The reason I think this should be included is there are several series for multiple different languages. They have Latin, Spanish, Japanese, Chinese, German, French, and Italian.

A language learners' forum

A forum for language learners. Challenges, group learning, resources, tips and guidance.

Themed Terms

A Google sheet with words sorted by themes translated to many languages sorted by language families. Feel free to contribute!

OpenCulture

Links to language sites with idescriptions. 48 languages to choose from.

Learning Languages

Quite useful guides for those who want to learn a new language, which include usefullness, the "chic factor", book recommendations and main difficulties you'll encounter. 21 languages are covered. On top of that there's a guide for those who are unsure which language they should learn.

Lang-8

A language learning platform where native speakers correct what you write. There's also a mobile app.

Jak będzie w surżyku?

A Facebook group for Slavic languages enthusiasts.

Goethe Verlag

Also known as 50languages or book2. Basically lets you learn any language from any other language in a list of 50, witg 1900+ words and approx as many stock sentences complete with native recordings for each language. There is also a phone app

LingoHut

Choose your mother language and follow all the courses that you want. There are many interesting languages as, for examples, Albanian, Persian, Urdu...

Global Voices

News site in read aloud in a bunch of languages, useful for parallel texts with audio

Bharatavani

The languages of India (lots of them). Part of the links doesn't work though

Yazyki Narodov Rossij

Mini courses for some minority languages of Russia (Komi, Russian Sign Language, Tatar, Chuvash, Yukaghir)

L-Pack

Language learning packs designed for immigrants in Europe

Językowa Siłka

A site with hundrets of articles regarding learning techniques and languages, from popular like English or German to the lessern known, like Maori or Thai.

Canguro English

A podcast; "Canguro English presents a podcast about language for people learning languages. Just another part of my mission to change the way the world learns English. Education should be FREE and FUN." One of the guests was Dan Everett himself!

Blog o nauce języków obcych

A polyglot's blog about language learning techniques.

Audio Lingua

Short audio recordings of native speakers talking about whatever they like (e.g. movie reviews, diary entries). 13 languages – 6810 mp3 files. You can filter them by the profficiency level, the sex of the speaker or the duration or the theme.

Anki - poradnik

The aforementioned guide. I'm going to write an English version one day :)

Słowniki

Dictionaries created by the author of the blog.

Polyglot Club

A site for language exchange.

Newspaper Map

Same as above, but with news sites.

Mówić.pl

A blog about language learning - recommendations, advice.

Learn Languages

Free language courses - 96 languages to choose from.

Keitah

A blog about language learning.

LanguageCrush

Reader app that works the same way as LingQ. But a more usable free tier and cheaper subscription for full access.

Arctic Megapedia

Information about & resources for a lot of minority languages spoken in Russia

Word2Word

A list of free online resources, including some endangered languages. 117 languages to choose from.

Web Corpora

Corpora of 15 languages, among them some Russian minority languages; plus many tools such as dictionaries and transliterators for other languages

Travelengua

There used to be tips and tricks for language learners but the link is dead apparently.

Peterlin

A blog about the languages of Africa, Ural and Caucasus.

Pararelltext

Here you can read texts in two languages simultaniously.

LangueDOC

Materials on the Archi, Khinalug, Nganasan, Enets and Tofalar languages

Languages Gulper

A website that quickly describes all languages by family for use by linguists and polyglots. Succint but no-bullshit

Hał ar ju, Marija?

A blog about languages and language learning.

Grammar and Language Courses

Articles regarding various elements of the language.

Glosbe Dictionary

Glosbe Dictionary is a multilingual dictionary spanning several languages.

Learn 101

A website to grasp basics of 104 languages

Szybka Wiedza

A blog about learning (not only languages).