Dar-r-r-ned RR's!
I am having trouble making the rolling R sound that is so common in the Spanish language. My husband has tried and tried to teach me, but my mouth just won't make that sound! When I try, it comes out like "derder-derder-derder." 
When my audio submissions are critiqued by other users they tell me to remember to make the rolling R sound when I am pronouncing a double R. I would love to; I have tried, but I don't think it's going to happen.
Am I just destined to have a Spanish speech impediment?
6 Answers
Hi Neffgirl,
Personally (I guess I was lucky), I never had any trouble making this sound. I grew up around a lot of cats, and I used to make this sound all the time when I would imitate the purring sound they made. Dee914 is right, though. There are tons of prior threads on this issue. Here is one of the better answers put forth by Lazarus regarding the mechanics of making this sound, and it can be found on this thread.
Touch the roof of the mouth''? Bad idea!
Your tongue must be touching your teeth on either side of the mouth, with the tip touching the alveolar ridge. The idea is that the air is forced to exit the mouth by pushing the tongue at the tip, but since we are keeping a certain amount of tension there, the tip of the tongue goes back after being pushed, only to be pushed over and over again, producing the vibration (2 to 3 times on average for every RR).
The method is very similar to the brrrr sound that you make when you blow air while keeping your lips closed, but too tight, so they vibrate. The RR sound does the same, but using the tip of the tongue instead of the lips.
More detail: the tongue should be flattened, so that it expands sideways, pressing hard against the teeth on either side. If the tip of the tongue is pressed hard against the alveolar ridge, and you try to blow air out, you should be able to block it (if you very try hard, you could even feel a bit of pain on your throat, but the air still doesn't come out). Once you have achieved this, you have to learn how to control the tension on the tip of your tongue: too slack, and the air will scape without rolling the tongue; too taut, and the air will be stopped altogether. The trick is to be able to control the right amount of tension on the tip, while keeping the sides very tense and air tight.
If the tongue is keeping the upper part of the mouth air tight, the strength of the air stream required to get push the tip of the tongue (and get the thrilled R) is rather low. If you increase the strength of the air stream, you have to increase the tension on the tip of the tongue to compensate. It is about correct muscle control in response to the air stream, not blowing air with inhuman strength or achieving high speed tongue movements, as some believe.
Additionally, here is an additional link that you might find helpful Phonetics
Hi Neffgirl!
I also had/have difficulty with trilling the R's. There are Many threads addressing this exact same issue! If you type in "trilling R's" or "rolling my tongue" or etc.... in the Search engine at the top of the Forum page and click enter, you'll see all kinds of previous threads regarding this topic! 
In the meantime, here's a thread I submitted a few months ago: link text
Hope it helps!
Most important thing, you will never be able to consciously move your tongue up and down fast enough...that is not even possible for anybody...and, besides, that is NOT what rolling the RR is.
Rolling the RR is caused by the tip of the tongue resisting air flowing out. The two forces equalize in a way that causes the tongue tip to vibrate.
If you hold the sound out, it sounds like a motor.
It sounds like you might be trying to make the sound at the front of your mouth and be trying to force it a little too much.
Trying thinking about making the sound further back in your mouth with the middle of your tongue with a gentle huff of air at the same time and hopefully a lovely rrrr will roll off the tip of your tongue
Lol, that'll probably make no sense but worth a crack Nige'
All the best, you will get there!
http://www.uiowa.edu/~acadtech/phonetics/spanish/frameset.html
click vibrantes then the second [r] and press play.
You can see how the sound is made from a cut away view of an animated head.
Hope this helps.
Ignore any suggestions based on words/sounds from English since the sound does not occur in English (except in the Scottish dialects). Unsurprisingly, the articulatory description provided by Lazarus (and quoted by Izanoni) is good but, unfortunately most people (unless they've had training in phonetics) have little idea where their tongues are and what they are doing (except to say, perhaps, "Well, it's in my mouth, somewhere.)
Careful listening to the samples in the link provided by Izanoni should help you to hear the sound (and, if you can't hear it properly then you will never be able to reproduce it correctly [since you will be unable to monitor your own production]).
