I speak Chinese without an accent.  When I speak on the telephone to Chinese people they assume I am Chinese.  It happens to me all the time - taxi drivers who refuse to let me in the car I booked because "the person they just spoke to on the phone (me!) is Chinese".  A Chinese employee at the British Consulate Shanghai didn't believe I was English when she called to ask about my son's UK visa - she was asking how long have I known [my name] and when I said - 'actually, that's me' she said '不好意思，我以为你是老外“. 　

As soon as people see my face though, it's a different story.  Taxi drivers feel they have to shout “虹桥机场” back to me several times and make aeroplane shapes with their hand to re-confirm.  I order a Starbucks in perfect Chinese, and the staff member says, in English, - "do you mean you want a small Americano?" - and I reply, yes, that's what I mean, which is why that's exactly what I said and you understood me perfectly.  

Last Christmas I ordered a roast turkey off taobao - and I spoke with the restaurant several times - about the exact time of day I wanted it delivered, how I wanted it cooked, what kind of sauces I wanted, and detailed instructions about how to get to my apartment block (including which other stops on his route were closest to me).  Then when he got outside my building, he called me down, and I went to the lobby and started speaking Chinese to him. He stood there mouth gaping and replied "err , ug, umm," then took the cranberry sauce and tried to explain what to do with it using sign language and the English words "this one, sauce, here, ok?". And that's because I look like a foreigner, not because I sound like one. 

This is really an insightful overview of the canonical tones of Mandarin. I have a couple of (potentially hair-splitting) technical comments!

One small issue I have with the motivation part of this article has to do with the distinction between category perception (which is what the infant study you cite discusses), and category production (what the remainder of your article is focused on). It would provide a stronger motivation for your discussion on production if you could make a stronger link between category perception in children to how adults learn to produce meaningful phonological contrasts in their non-native language(s).

Also, to be a little more specific about the finding of this study, and more recent online studies of what is called the "perceptual magnet effect": the finding reported in the article you cite is that even prelinguistic infants show signs of becoming more sensitive to the sound features that underlie phonological contrasts in the language input that they have received (from their parents, for example). Similarly, even at an early age, infants show signs of steady desensitization to contrasts that they have been conditioned to ignore given the language data they have been exposed to. This distinction is important because there is no clear evidence to suggest that children know they are learning one language, or two, or 20. Children do indeed ultimately separate languages due to their ability to pick up on cues like prosody, rhythm, syllable structure, etc., that differ between the systems they are exposed to. My point here is that children bootstrap their first language(s) from input they receive, and part of this bootstrapping process involves deciding which sound components are meaningful, and which aren't.

Thanks for taking up the challenging task of explaining tone production in Mandarin -- this is a very helpful (and fun) guide!

Great article, very clear. Thank you. I knew nothing about Chinese.

Phonetics is very important for language learning. However is learned late or not at all. I should be the very first thing to learn.

In Spanish we have 5 main vowels. When I learned Portuguese, which is very close to Spanish, it was hard to pronounce and to understand because they have more vowel sounds. We, Spanish speakers, reduced those sounds to our 5 vowels. I had to study some phonetics and it was very helpful in my learning. And that proved useful for learning French or German.