No. And the simple reason is that you can learn them even faster with flashcards than without.
Let's start with what pointy-headed ivory tower types have to say about flashcards. There's been a ton of research over the years showing the benefits of flashcard use. Luckily, I don't have to sift through any of that, because some researchers have recently done it for me. Time sums it up as follows:
The scientific literature evaluating [learning] techniques stretches back decades and across thousands of articles. It’s far too extensive and complex for the average parent, teacher or employer to sift through. Fortunately, a team of five leading psychologists have now done the job for us. In a comprehensive report released on [January 9, 2013]…, the authors… closely examine 10 learning tactics and rate each from high to low utility on the basis of the evidence they’ve amassed. …That emphasis is all mine, baby. And, if we turn to the study itself, much of the data on flashcard use was actually directly from language learning:
[A] learning strategy that is highly recommended by the report’s authors is practice testing. Yes, more tests — but these are not for a grade. Research shows that the mere act of calling information to mind strengthens that knowledge and aids in future retrieval. While practice testing is not a common strategy — despite the robust evidence supporting it — there is one familiar approach that captures its benefits: using flash cards. …
All [but one other technique] were rated of “moderate” to “low” utility… because either there isn’t enough evidence yet to be able to recommend them or they’re just not a very good use of your time. Much better, say the authors, to spread out your learning… and get busy with your flash cards.
A sizable majority of studies using paired-associate materials have included foreign-language translations (including Chinese, Iñupiaq, Japanese, Lithuanian, Spanish, and Swahili) or vocabulary words paired with synonyms.So the ivory tower's opinion on flashcard use is hardly ambiguous, and the only thing I'll add is that flashcards will be most effective when combined with other kinds of exposure.
I could probably end this post right here, but let's dig in a little deeper.
Let's take an example from the numbers I used in my last post. Let's say it takes 15 exposures to learn something (the actual range appears to be 15-20). If you're getting just one hour per day of exposure to the target language, this means you'll see the 250th most-common word every 1.7 days, and you'll hit your 15th exposure on about the 26th day, at which point you should know the word.
You can probably lessen the 15-20 repetitions a bit if you make sure each of those exposures is meaningful by looking up the definition as you encounter them. However, each time you need to repetitively look up the definition, you're wasting a certain amount of time.
But let's say instead that you made a flashcard of it the very first time you encountered the 250th most-common word, which statistically should have been no later than your second day of studying the language. You make a flashcard of that word, put it into your spaced-repetition system, and then use your SRS flashcards primarily during trapped time. If you keep up with your flashcard reviews in your SRS, your SRS will not only have you review that word at the optimal time to minimize repetition but maximize retention (thus reducing the 15-20 exposures figure), you'll also be likely to recognize the word every subsequent time you see it and never need to look it up again. What's more, if all that fails you and you still forget a word that's on a flashcard (which, statistically speaking, you're going to do from time to time), if you can at least recognize that you've made a flashcard of it (which I've found I can almost always do), you still won't need to look it up again, as you can just take a look at the flashcard you made previously.
Going without flashcards simply doesn't make language learning any faster, even for the most-common words. If you look up unknown words as you come across them without any use of flashcards, you'll end up doing repetitive look-ups of words as you forget them—a problem that is avoided with the use of flashcards in a systematic spaced-repetition system. If your plan is to learn only from context without even looking anything up, I've discussed before how inefficient that is; before you learn a given word, you're going to get exposed to it a bunch of times before you have any idea of what it is, a problem that could be remedied by looking it up.
(This is the much-touted "learn like a child" method, which is horribly inefficient, as explained here.)
I'm actually putting the kind of flashcard use I recommend above into practice for the most-common words in Korean right now. When I think about doing it Randy's way (looking up things repetitively as I come across them or trying to learn from context), not only can I see myself getting frustrated from needing to repeatedly look up words or struggle with trying to catch things from a context in which I can currently understand very little, but I can't envision any combination of factors whereby Randy's method could help me learn faster than the method I'm using, which also incorporates flashcards. I'd drop my method in a second for a faster way to learn, but I'm just don't see that in a flashcard-free method.
This post is part of a series on using flashcards written in response to Why I don't use flashcards (and you shouldn't either) and other related posts on Yearlyglot.com.