A great way to dive head-first into Spanish is to start checking out the most popular free resources available online and seeing what works for you and what you like. Here's a list of my favorites with descriptions for each, check each one out and bookmark your favorites. Oh, and don't forget, you'll be getting my next e-mail about language exchanges and which the best ones are in 3 days, remember to look for it in your inbox.
1. The best dictionary/translator/conjugator in the known universe: SpanishDict. This site is fantastic, it's by far my most-used and most valuable reference tool, it's the best dictionary I've tried and, also...
2. They have the best conjugation tool (here) I've found, and I really like their translator setup on the front page where your requested translation is run through the 3 major translation engines (Google, Bing, and SDL) all at once and you see all 3 so you can just pick the best.
3. Urban Dictionary: Yes, I'm serious, a Spanish-learning tool. I have found no better method, resource, or reference for looking up Spanish slang and profanity, none. This is the best and nothing else is even close. They have Mexican, Colombian, Argentinean, Peruvian, Dominican, etc.--you name it, it's there. Now, they don't haveeverything, I've certainly run across slang words that weren't in there, but they've got the most in one single place by far. Look here before you look anywhere else, they're the most likely to have it.
4. Forvo: This is such a fantastic site, enter any word and listen to a native speaker pronounce it. Ever noticed that when you're reading a foreign language you have trouble figuring out how to pronounce the words because you know that how it would be pronounced in English, with that spelling, probably isn't correct? Problem solved.
5. Notes in Spanish podcasts. You don't need the worksheets they tout (useful, but not necessary and, in my opinion, overpriced at $50 per level). Just start in the beginner section, go back to the first podcast (here, I made it easy for you) and start listening to them in sequence.
6. 168 Spanish children's books you can read online for free at the International Children's Digital Library. I thought this was so fantastic that I devoted a whole post to it, and added some more stuff of a similar nature in there you'll probably be interested in, check it out. I love using children's learning material that's in the language you're trying to learn because it's targeted towards people (children) who have only a basic grasp of the language and are trying to learn it, which is precisely what new adult language-learners are. Not only that, but it's usually a lot of fun and therefore much easier to pay attention to and endure than boring textbooks and workbook exercises.
7. Anki, the vocabulary memorization tool to beat all vocabulary memorization tools and methods. It's something called SRS, which stands for Spaced Repetition Software, and it's essentially a digital flashcard program that periodically brings up old vocabulary for review so that you don't forget it and all of the timing/spacing has been handled for you, if you're the type of person (many aren't) who likes to learn vocabulary this way, then this is just the thing for you. But, like I said, keep in mind that you need to like learning things by rote memorization and many people don't.
8. The Wikipedia entry on Spanish grammar: This is more of a reference than anything, I wouldn't recommend trying to actually learn Spanish grammar by reading this article from start to finish, that's not going to work well, but I did find myself referencing it frequently to check on things.
9. I wrote up an entire post dedicated to how to use Spanish-language TV shows and movies to learn Spanish called: The Telenovela Method of Learning Spanish, plus I put together the most comprehensive and accurate (no dead links! unlike every other list I checked...) list of websites where you can watch streaming Spanish-language TV online for free here: List of Best Free Sites to Watch Spanish-Language TV Online.
10. The Spanish section of the BBC's language-learning page is fantastic, tons of free videos, newscasts, radio broadcasts, lessons, etc.
11. The blog formerly known as 'Actualidades' but currently called Zambombazo: this guy is super-active, posting really good quality stuff about 2-5 times per day. What he does is use current pop-culture media like music videos, short clips of TV shows, pictures, news stories etc. that are from a Spanish-speaking culture somewhere (he does a good job of changing up the countries and giving you a good variety) and then turning it into a little mini Spanish-lesson where he has a series of questions that either you or your students are supposed to answer afterward. It's just one guy doing all of it and the amount of work he puts into this site is just unbelievable, either he's retired or independently wealthy, there's no other explanation.
12. Fluent in 3 Months is a general language-learning blog run by 'Benny the Irish Polyglot' and he's currently in the Philippines and focusing on Tagalog right now, but this is one that anyone learning any language for any reason ought to be subscribed to, Benny puts out awesome stuff and his lifestyle is fascinating and something I hope to somewhat emulate eventually: what he does is move to a new country for 3 months at a time during which he forces himself to get conversationally fluent in the local language (in 3 months, hence the name of the site). So far he's done Irish, French, Spanish, Italian, Portuguese, and German using this particular method (he also speaks Esperanto). Fascinating stuff, good writer, and he's walked the walk (taught himself multiple languages) and consequently earns the right to talk the talk and be taken very seriously.
I especially liked his post on 'the smartest decision you will ever make', which does an excellent job of explaining his philosophy on language-learning.
13. Spanish Only. Ramses taught himself to speak Spanish all on his own, just like me, but has a very different approach, which is actually part of the reason I'm including him: people have different personalities and tendencies and therefore different things work for different people and I want to include as many options as I can so that you can find something that works well for you. Ramses is a really strong advocate of taking a 'silent period' during the first few months while you're learning Spanish and ONLY listening/reading to it, NO speaking, he really believes that speaking too early is highly detrimental to the beginner's learning process--I find the opposite is true for me, but it absolutely does seem to work well for certain people, and it's a blog that I read and highly recommend subscribing to.
14. Language Fixation is another great language-learning blog that I really like due to his analytical approach and extreme emphasis on numbers, analysis, record keeping, setting very specific goals, and in particular doing a great job of keeping track of his results and then publishing them for other people to see. He's also of the input-only-to-begin-with school like Ramses but has also published some great advice on how to get speaking practice on your own that I found to be especially insightful and valuable.
15. Randy over at Yearlyglot is on a similar sort of program as Benny in that he has a set time (one year) to learn each of his languages and then at the end of that year he travels to the country in question to test himself (he's currently in Italy but has already started on Turkish which is what he's learning for this year).
16. My personal favorite forum regardless of what language you're learning, and probably the biggest language-learning related forum on the internet, is HTLAL (How to Learn Any Language). Keep in mind that people there are very analytical and logical about how they go about doing things, but that has resulted in a level of quality of information that you won't find anywhere else. I especially recommend people check out Iversen's ridiculously long 'Guide to Learning Languages' (set aside a few days for that one).
17. Foro de Español is a forum that I don't frequent much but that's only for lack of time. It's huge and specifically for people trying to learn Spanish (it's the only one I know of entirely dedicated to Spanish).
18. Omniglot forum is in a very similar vein to HTLAL except that it's not quite as big (though it's still very active).
19. How to Not Sound Like a Gringo - The 17 Most Common Spanish Errors and How to Avoid Them is a post that I did where I covered what I, and other polyglots and native Spanish speakers (who deal with English-speakers trying to learn Spanish a lot), have found to be the most common 'gringo errors', that is errors frequently made by native English-speakers who are trying to learn Spanish.
20. SpanishDict's YouTube channel is loaded with videos covering tons of Spanish basics such as greetings, food, the subjunctive, various verb conjugations, basic grammar, the conditional, the future, etc.
21. LearnaLanguage.com has amassed an enormous database of resources for lots of different languages, with Spanish being one of their largest sections: lessons, games, activities, word lists, dictionaries, culture, etc.
22. Manners in Spanish - The Basics of Being Polite in Spanish-Speaking Cultures is a post that I did about basic manners and faux pas in Spanish-speaking cultures--now, keep in mind, that "Spanish-speaking cultures" is a HUGE and very, very diverse group of people, and to try and boil them down to common characteristics is very difficult and inevitably dangerous because you're always going to miss things or include something that, although it may be common to most, doesn't apply to a certain country or city/area within that country, etc. Please keep this in mind. But, they are a good general group of guidelines, particularly if you restrict them to the major Latin American countries (Spain is very different and more 'European', culturally, than 'Latino') such as Mexico, Colombia, Argentina, Venezuela, etc.
23. Internet Polyglot has tons of free online lessons (you can create your own), tutorials, games, slideshows, with a fantastic layout and navigation.
24. LingQ is a fantastic resource that focuses on learning as much vocabulary as possible and meeting and socializing with other language-learners, specifically those who speak your target language and are learning your native language, so it sort of functions secondarily as a language-exchange.
25. Spanish Sentence Starters and Filler Words (Muletillas): The Grease of the Language Gears - This is a post that I wrote that covers something known in Spanish as "muletillas", which are the Spanish equivalents of things in English like "umm", "well", "sort of", "like", "so, if...", "then", "in other words", etc. That is, little colloquial phrases that really distinguish someone who speaks like a native versus someone who learned from a textbook.
26. SpanishPod101 is a sort of podcast-based website that releases new Spanish lessons for you daily, its primary appeal being that you're constantly receiving new, updated material that's based on current events (always a plus, makes things interesting).
27. BabLa's Top 100 Language-Lovers of 2011 is a list done every year of the Top 100 language blogs (yes, I'm on there! :D ) that serves language-learning enthusiasts as a fantastic list of blogs to consider subscribing to.
28. Defense Language Institute has lots of free language lessons for several dozen languages.
29. Lyrics Training uses music videos and accompanying lyrics to help you learn a foreign language. This is a good complement to my Shakira posts.
30. How to Respond in Spanish Like a Native: Comebacks and Colloquial Responses is a post that I wrote about the most common comebacks and answers that native Spanish speakers will typically use in conversation--remember, my focus is really on teaching you to speak normal, everyday, colloquial Spanish so that you can go to a Spanish-speaking country and come as close to sounding like a native as possible.
31. Lang-8 is actually one of my favorite resources, it's one of the few that I really, honestly make a point of using regularly. What you do is write up a short passage in the language that you're learning and then native speakers of that language will proof-read and correct it for you, and then you do the same for them (it works on a point system).
32. NewspaperMap.com is a WONDERFUL resource for the language-learner: it allows you to find all of the newspapers in the country of your choice, plus you can search via language which is especially helpful. I know that I emphasize speaking but I think that once you get to a high-beginner or intermediate level you should really put a lot of time into reading in your target language as much as possible.
Bonus (actually, I forgot, and a reader mentioned it so I came back and put it in): The WordReference Forums - these people are fantastically helpful (though please remember to search before asking a question to see if it's already been addressed) and the forum has been around forever and contains enormous amounts of information.
Well, I really hope that was valuable to you, feel free to send any feedback to me at firstname.lastname@example.org and remember to look for my next e-mail in the series about language exchanges, you'll see it in your inbox in 3 days.