Sometimes I have a problem in distinguishing "L" and "R" in spoken English. I wonder if native speakers distinguish well the pronunciations of "L" and "R".
For example, how about "leave" and "reave" or "elect" and "erect"?
There are always some people who are exceptions, but yes, native English speakers in general do clearly and easily distinguish these sounds.
I'm not a linguist, but from what I've read and seen it tends to be fairly common that native speakers of a language will easily distinguish phonetic differences that affect meaning, while ignoring those that don't. I'm guessing your native language doesn't distinguish these sounds: perhaps one of them isn't used, the same letter (or equivalent) can represent either sound, or which sound is used in a given word depends on the speaker's dialect.
Most English speakers would have a similar problem learning a language in which the sounds of k as in skip (not aspirated) and k as in kill (aspirated in most dialects, almost pronounced khill) are distinguished (affecting meaning). As a native English speaker I can hear the difference if I think about it, but as far as understanding spoken English goes they're both the sound of k. (Thanks to Peter Olsen for the example.)
English speakers distinguish these sounds almost perfectly. Certainly with well over 99% accuracy. As pointed out in another post here, any phonemes that create a difference in meaning in a language (in a substantial number of environments) will be clearly and reliably distinguished by native speakers.
If you are a Japanese speaker planning to speak English with speakers whose first language also distinguishes /l/ from /r/, then it is ESSENTIAL that you learn to make these sounds so that they are distinguishable. Even if you don't remember in every case, you need to be able to make these sounds completely distinct. It's even better if you can train yourself to hear the difference. This is a much more difficult task, but it's doable. Many very good Japanese speakers of English find it difficult to hear the difference. However, all very good speakers of English can produce the sounds correctly.
I would say that not only do most native speakers have no problem distinguishing them, but that they sound so different that the idea of mixing them is surprising and therefore somewhat comical (sometimes, unfortunately so, as in stereotypical mockery of Asian speakers).
Short of speech impediment, no native speaker mixes these letters. Children sometimes have trouble with r and l (and especially r), but they usually become a "w" or "uh" sound, not intermixed. So, in order to sound natural, it's really, really important to get this right.
I say this with a lot of sympathy because as a native English speaker there are many sounds in other languages which I can't properly distinguish, let alone pronounce. (That Czech Ř kills me.) Or, perhaps more similarly to l and r, the two pronouncations of ch in German.
I don't think most native speakers experience any such difficulty; but the fact is, distinguishing phonemes is only a small part of understanding speech.
So when we're listening to speech, we're paying attention to a great deal more than properly pronounced words: we're also employing our knowledge of grammatical rules and idiomatic constructions and particularly the discourse context, from the nature of the immediate topic to the entire cultural background we share with the speaker. We have a great many more cues than the vocal sounds to tell us what any given word in any given context has to be.
Just for example, I'd be willing to bet that very few people have ever even heard the word "reave"; it's a literary word, virtually nonexistent in the spoken vocabulary, and even in literature "leave" is more than 10,000 times as frequent according to Google Ngrams. Moreover, how likely is it that a word meaning "rob or steal by force in a raid" would occur in a context where "leave" would be intended. If you mistakenly said "reave" for "leave" everybody would automatically correct it to "leave"--most people wouldn't even notice the need to filter it.
So whether or not hearers are able to distinguish the actual sounds they hear, they have no difficulty recognizing the sound which should be there!
In elementary education (at least in California), /l/ and /r/ are actually something that some (i.e. many) children struggle to pronounce. Generally these children also have trouble distinguishing the phonemes, but don't have any trouble with distinguishing actual words, for which they rely on context. Creating situations where the children cannot rely on context to distinguish meaning (e.g. playing word-games pronouncing minimal pairs) helps highlight the phonetic difference to them, so that they learn to distinguish the sounds. Adults and older children often find such mispronunciation humorous, to the detriment of such a child. Such difficulties generally vanish by the first grade (the only first grade students I knew personally who had difficulty with /r/ vs /l/ were of Japanese descent).
Generally, yes. But it's not an ability held solely by native English speakers. People with a first language that observes a difference between /l/ and /r/ tend to be able to grasp that difference more easily, and the /l/ and /r/ difference is observed in a number of non-English languages.
Similarly, sounds that don't exist, or are far less common, in English (like the alveolar-tap used to make part of the りゃ sound) tend to be much harder for native-English speakers to identify and reproduce. For example, it's often difficult to hear that りゃ is not the same as リヤ, which also may make it difficult to learn to produce りゃ instead of リーヤ or リヤ.
If you really wanted to get into the specifics of who tends to be able to identify which sounds, in English that field of study is called Phonotactics. (But that may be more research than you wanted for this question.)
Even though I'm not a native speaker, I can clearly hear the difference, it's much bigger than between, let's say U and Ü!
PHYSICALLY L and R can't sound similar, as your tongue has completely different shape in each case! (note: sorry to English language teachers - I don't know the proper terminology)
While "L" is pronounced with tip of your tongue twisted up (probably resting on alveoral ridge), the "R" is pronounced (depending on surrounding sounds) with front or back on your tongue raised up to (or resting on) hard palate. Different shape, different airflow, different resonance. Dramatically different sound!
OK - edit! I looked it up and it is even different:
I'm not a native speaker, but me and my many friends do speak English as a second language. It's not a problem for us when we are listening to a native speaker, but it's hard to distinguish L and R when a Korean or Japanese speaks.
I remember we mistook a Korean song lyric "ring a ring a ring" for "ling a ling a ling".
(song in question: https://www.youtube.com/watch?v=4h1SixKJSKs)
You might be completely capable of discriminating these two sounds, but not remembering that they use two different letters. Try to pay closer attention and see if that is the case.
For example, I know a person who cannot tell whether a colour is blue or turquoise, but when seen side by side, can always identify that the both are different and one is bluer or greener than the other. Therefore, it’s not an issue of colour blindness, but instead of memory and attention.
This could be the same with you, when you could hear both /r/ and /l/ one after another and identify that they are distinct sounds, but if you wanted to pick a letter to represent either sound, you couldn’t. So your issue might not be sound-deafness or indistinction.
You can test that by taking recordings, cutting out the culprit sounds and listening to them or asking a native speaker to help you. Forget about letters and your difficulties, assign a number or colour to one or another sound, or just a yes/no. Focus on the properties of the sounds themselves, figure out if you can hear that they are different, not that they belong together or apart.
As the other answers say, most native speakers have no problem with differentiating pronunciation. However, I'd like to point out something about deviations from this norm.
First, there are quite a few native accents, many being characterized by their unique R sound in fact. However, even between communicators with vastly different accents communication is fairly easy, and each can even correctly spell most words spoken by the other.
Second, even within a single accent, R and L and other letters might be pronounced in different ways depending on context or spelling. In British English, for example, R is usually pronounced softly ("ah") at the end of a word like "colour", and strongly ("rr") at the start of a word like "really". In some British accents, the word "are" sees the R pronounced softly while the slightly different word "aren't" has a strong R sound. Most importantly, these differences are rarely learned through explicit instruction - they're picked up through observation. Children recognize these different sounds and have no trouble mapping them to the word spellings they learn.
Third, people from certain non-English backgrounds who are learning English or else never take the time to develop their pronunciation may have trouble pronouncing certain letters in English with phonemes that don't exist in their native tongue. Sometimes (and perhaps politically incorrectly, but certainly most illustratively) the resulting accent is referred to as "engrish". These, too, are fairly easily understood by most native speakers.
Fourth, there are some typical speech impediments, such as rhotacism, which cause the afflicted to drastically mispronounce R and/or L. These people are still easily understood by other native speakers.
Ultimately, my point is this: even among native speakers, pronunciation of R and L and any other letters can vary greatly for many reasons, and yet all are generally well-understood. It's one of the interesting powers of the human brain which language reveals: the ability to effectively match vaguely similar speech patterns to the ideas they're intended to represent.
In short, there is no universally perfect pronunciation in English. As long as it's close enough, it can be understood, and that's just fine. You can only "improve" your own pronunciation by using the same accent as the one which the person you're communicating to is most familiar with.
Yes, We generally distinguish it well. In my experience, Japanese learners of English generally pronounce both as "l", giving us the stereotypical joke about "flied lice". I had a Japanese friend named Hiromi and she pronounced her own name as "Hilomi", so I think part of the confusion goes back to whoever decided how to transliterate Japanese into English.
So, the sound that most Japanese make for "r/l" is probably "l". The best advice I can give for how to actually pronounce "r" is to listen to a growling dog. We write it imitatively as "Grrr". If you can then tell the difference between this growling sound and the softer "l", it might help.