Hello everyone. I'm going to start by saying I am very new to Japanese and a native English speaker. I know many people advise against using romaji, but for me it helps clarify how things are pronounced. However, as I was studying the Hiragana ら、ろ、れ、る、and り I noticed the pronunciation was somewhat like a "d" sound despite the romaji all beginning with r. I watched several videos on pronunciation, but I can't seem to get it as I don't really visualize where my tongue is in my mouth when I speak. If anyone has tips to help me, I would appreciate that. ありがとう.
The japanese R is a mix of R and L, it can be hard to pronunce so I recommend watching a video on how to say it. If you just keep practicing you will eventually be able to pronunce it with ease . Also a extremely good app to memorize hiragana and katakana is "hiragana quest" (it does cost a little money but it's totally worth it) if ur able to remember all the characters you won't need to use romanji (obviously I don't know if you already have an app for hiragana and katakana, but I highly recommend "hiragana quest" and it's definitely worth the money) . Also if ur going to use hiragana quest I would also recommend writing the important information in a textbook (like the words you use to memorize the characters, or the building blocks for the characters).
The Japanese R sound is called an alveolar tap, which means you put the tip of your tongue briefly on the ridge behind your top teeth and pull it back to make the sound.
To people who don't have an alveolar tap in their native language, their brains try to map it to the closest sound they do know. D is also an alveolar sound, which is why you hear it as a D.
If it helps to produce the sound, say "butter" quickly (more like "budda"). The consonant in the middle will be close to the Japanese R. But don't worry if you can't make the exact right sound; Japanese has so few phonemes that you can miss the pronunciation and still be understood as long as you aren't substituting another Japanese consonant. You can pronounce ら with a straight English R or L sound and people will have no problem with it.
This may or may not be helpful, but this is what helped me.
Depending on what English dialect you have... you may pronounce "water" with a soft R. If you say "water" with a hard R it may not help.
I realized that way I say water emulates the Japanese R, so I keep trying to emulate that sound whenever speaking. There are a few other English words with similar sounds. I recommend finding a word that emulates that effect and trying to practice in that way.
This may or may not be helpful, but this is what helped me.
Depending on what English dialect you have... you may pronounce "water" with a soft R. If you say "water" with a hard R it may not help.
I realized that way I say water emulates the Japanese R, so I keep trying to emulate that sound whenever speaking. There are a few other English words with similar sounds. I recommend finding a word that emulates that effect and trying to practice in that way.
. Also a extremely good app to memorize hiragana and katakana is "hiragana quest" (it does cost a little money but it's totally worth it) if ur able to remember all the characters you won't need to use romanji (obviously I don't know if you already have an app for hiragana and katakana, but I highly recommend "hiragana quest" and it's definitely worth the money) 
. Also if ur going to use hiragana quest I would also recommend writing the important information in a textbook (like the words you use to memorize the characters, or the building blocks for the characters). 
