The most fluent conversation I’ve ever had in German while still learning it happened when I got drunk with an Austrian friend of mine.

When I say 2 techniques, it's actually just one: shadowing. Essentially you take a recording of a piece of speech and memorise it. You then practice saying it at the same time as the recording. When you feel like you are able to say it, play the recording in headphones and record your voice. Then compare your recording to the original recording.

I used news casts to practice because it was easier to find audio clips that also had transcripts I could read -- however an audio book would be ideal if you can get your hands on it. I ran into a problem just having facility with the succession of sounds, timing and tones. My "second" technique was to do this with music. I memorised a variety of popular music and then went to karaoke 3 times a week :-) Probably this helped me the most.

I still struggle quite a bit with tones. Japanese does not have accents on words, but it has 2 tones -- either rising or falling. Getting the tones right is often the difference between being understood or not. At first I could not hear the tones but practicing example sentences that used homonyms with different tones helped me quite a bit.

As I said, I never really had to struggle with learning how to pronounce a sounds -- it was much more in selecting the correct sound, or refraining from using English dipthongs, etc. However, I've taught English to Japanese students who have real difficulty learning how to make certain sounds. I have found that being very specific about how the mouth moves, where you put your tongue, how to use your breath, etc makes all the difference. Probably the best reference are textbooks meant for people who were deaf from birth. After that it's just practice and shadowing is the best technique I know about.

The main source I've used is 日本語アクセント入門 by 松森晶子. It's primary focus is on Standard Pronunciation, but there are lots of good illustrative tidbits that incorporate examples from other dialects as well.

Highly recommended!

https://en.m.wikipedia.org/wiki/International_Phonetic_Alpha...

http://www.nativlang.com/linguistics/ipa-pronunciation-lesso...

Some people cannot, at first, hear certain sounds in a new language. Usually a language teacher makes them aware of these sounds. If that fails, one could hire a phonetician (like Henry Higgins in the movie "My Fair Lady"), a linguist skilled in the way one shapes ones vocal apparatus to make sounds in a particular language or languages. Some language textbooks provide descriptions of how to do this.

Question 2: A language lab.

https://en.wikipedia.org/wiki/My_Fair_Lady

The jury is still out on that. See https://en.wikipedia.org/wiki/Critical_period#Linguistics.

My experience has been that people get to a "good enough" level in a second language and their motivation for working hard goes down dramatically. Children, on the other hand, have a lot of incentive to work hard on their language every day. If you've ever known a child with a speech impediment, you can see how tortuous it is to speak differently than your peers.

The other thing that colours my judgement is that every person I've ever met that has tried consistently to remove their accent has succeeded. However it's a 365-day per year, multi-year project. I've met very few people willing to undergo that experience.

Citation?

This doesn’t match my experience: I have heard at least a few hundred non-native speakers of my native language (Russian), and every single one of them had an accent, obvious after just a few words. The few exceptions were be native speakers of other slavic languages, but even then I suspect they learned Russian as kids.

I know other people from the area that have lived away from home for 20 years and still sound exactly how they used to!

Also my accent comes back when I speak to people from "home".

My Spanish also improved with alcohol and a few months travelling around south america, where people are far less picky about the language than they would be in Spain and not too many local people speak English.

It's really that simple.

(1) Get an understanding of how to make the sounds from native speakers.

(2) Make a list of all the words you know you don't have a good pronunciation of.

(3) Repeat the words to yourself regularly.

That's it.

Some words will come easier than others, and ones you have mastered can be removed from the list.

I find it's best to do them in small blocks. Five at a time, or whatever you can easily hold in memory.

You have to watch their mouth shape and tongue position.

In the end it comes down to practice with specific intent of improving your pronunciation. Hiring a voice coach would be the next step.