Language

dictionaries / thesauri

Canadian Spelling Dictionary | +
Canadianisms on Historical Principles
Dictionary.com | Thesaurus.com
NetLingo Dictionary (Internet terms)
Ninjawords
OneLook Dictionaries (metasite)
Oxford English Dictionary [UK]
Visual Dictionary
Visual Thesaurus
Word Hippo
Wordnik

rhyming dictionaries

Prime Rhyme
RhymeBrain
Rhyme Desk
Rhymer
RhymeZone
WikiRhymer

slang & neoteric

Dictionary of English Slang [UK]
Open Dictionary
Slanguage
Twists, Slugs, & Roscoes
Urban Dictionary

translation

BabelFish (translator)
The Dialectizer (humour)
DeepL (translator)
Foreignword
Tarjim (Arabic)
Travlang
WorldLingo
WWWJDIC (Japanese)

learning

BBC Languages
Digital Dialects (learning games)
Foreign Languages for Travelers
French in Action
Language Bookings (study abroad)
Live Lingua
Numbers in Over 4500 Languages
Radio Lingua Network
Real Kana (hiragana/katakana)
she shashishalhem (Sechelt language)
Teach Yourself Japanese

Esperanto

Esperanto: Multlingva Informcentro
Esperanto-USA (ELNA)
Kurso de Esperanto
lernu!
TEJO
Universal Esperanto Association

quotations

The Essence of Quotations
Famous Quotes
Taglines Galore
ThinkExist
Wisdom Quotes

grammar/style/writing

BibMe (bibliography generator)
Common Errors in English
Grammar Bytes
LitReactor

(copy)editing

ACES | Words on Words
Editors' Assoc. of Canada
Technical Editors' Eyrie

word finders

a2z WordFinder (word pattern matcher)
Adjectives Starting … | Nouns Starting …
AllWords
Anagram Archive
Anagrams Generator | and more!
Best Word List
Internet Anagram Server
MoreWords
Unscramblex
The Word Finder
YouGoWords

etc.

Acronym Finder
The Alphabetizer
AskOxford.com
ClichéSite.com
CRPuzzles (word puzzles)
The Etymology Nerd (Adam Aleksic)
fonetiks.org (pronunciation guide)
Forvo (pronunciation examples)
Friedman's Site (clichés & more)
Fun With Words
HandSpeak: Visual Languages
Inuktut Tusaalanga
Latin Phrases
LitReactor
Lorem Ipsum
Malaphors
Merriam-Webster Center | Games
NaturalReader (text-to-speech)
North American English Dialects
Ngram Viewer (Google)
Parlo (Language. Culture. Life.)
PhoNETic
The Phrase Finder
The Phrontistery (obscure words, and more
Psycholinguistic Database (Medical Research Council)
SCOWL Kevin's Word List Page)
Society for Technical Communication
Tip of My Tongue
Wilton's Etymology Page
Word Detective
Word Information (word components)
Wordsmith (word-a-day, anagrams)
Word Spy (neologisms)
Word Wizard
World Wide Words [UK]
Writer's Market
Wylie Communications (Ann Wylie)