In the very beginning, when you hear the different tones juxtaposed one after another, you can hear that there’s a difference, but articulating the difference or reproducing the tones seems like an impossible task. It will take some time for the “stupefication factor” to wear off to the point that you’re actually willing to try to pronounce the different tones.
After prolonged exposure, you can hear the differences between the tones, and can even reproduce them, somewhat. Memory of tones lasts only about 3 seconds, however, after which if you don’t hear them again, recalling them is hopeless.
Individual Tone Success
After a lot of hard work and even more exposure, you will be able to produce a given tone in an isolated context when making a deliberate effort. Congratulations! This is actually no easy task! At this stage, however, you will still make TONS of mistakes when actually trying to use words in conversation. Except for the most common words/phrases (“ni hao,” “xie xie,” etc.), you can ONLY pronounce isolated syllables correctly, when concentrating. You still cannot correctly identify the tones in a new word that you hear, though.
Familiar Double Tone Success
Way after your initial double tone success with words like “xie xie,” you’ll start to get the hang of tone combinations in familiar words. Pronouncing these correctly in conversation is still quite a challenge, however. You probably still let English sentence intonation affect your tone pronunciation, too. (See Sinosplice’s Tone Pair Drills for more help in this area.)
If my own learning experience is at all typical, you will find the order of difficulty of tone combinations to be similar to the following (easiest to hardest, top to bottom, with combinations of roughly equal difficulty in the same horizontal row):
2-2, 4-2, 1-4
2-3, 3-3, 1-3, 2-1
3-4, 3-1, 1-2
Complete Double Tone Success
After you learn to pronounce all the unique tone combinations for words you know, you will soon be able to apply them readily to less familiar words. This process gets easier and easier with time.
Multiple Tone Success
Believe it or not, 3 characters in a row can sometimes throw you off even when you’ve got the “doubles” down pretty well. It takes conscious effort. If you can do the “doubles,” though, then with some work you can do any combination, simply by breaking it down into a series of doubles. (E.g. a 1-3-2 combination is like a 1-3 overlapping a 3-2.)
Congratulations, you can pronounce Mandarin’s tones accurately consistently now, and it feels natural. You now have the Holy Grail of Mandarin study. (There’s still plenty to work on, though, such as entire sentence intonation and narration techniques…)
(See also “The Five Stages to Learning Chinese” on Sinosplice.)