I'm amidst an obsession. I can't stop listening to Cantonese, wanting to hear Cantonese or learning every scrap of Cantonese vocabulary. My ears seize passing words and suck their vital essences, for future reference of course. Bizarrely, or not so bizarrely, my ears are quite intuitively seizing the language. It is quite possible that my Mandarin brain has finally connected the dots and has united the language engine of Mandarin with the Cantonese vocabulary and knowledge that I've been diligently gathering for 14 years. I'll immediately recognise unknown words as cognates in Mandarin and understand the gist of what is being said. Natural phrases spoken rapid and naturally are hooked in by my senses and sensed by my brain: I know what is being said without knowing why I'm understanding it. It may be that I'm learning the language as a Mandarin speaker rather than as an English one. Or maybe I'm enjoying the best of both worlds. A friend noted: I don't have the same inaccuracies as a person not from the province, I can pronounce and "hear" the sounds that don't exist in Mandarin with the tones that don't exist in English.
One odd side-effect is that when I switch back to Mandarin, at first it is completely alien, and the a complete relief and flowing into my intellect without any problem with understanding. The problem with switching between languages has always been a problem for me, and to be honest it probably helps that I stay in one language. Chinese students have always integrated English with Chinese, so it is not hard to understand how they have no issue switching; or, for that matter, have such trouble dis-integrating their English from the pernicious influence of their mother tongue.
Cantonese is a dialect of Chinese relatively uninfluenced by the races that took the Imperial throne in the north. According to one of my early lecturers Mandarin was simplified because the Mongols, who took Beijing as their capital for less than 100 years, couldn't get their tongues around end-sounds. Perhaps the Manchus, who ruled the last dynasty of Imperial China before it became a Republic, also aided in the reduction of tones down to the mere four (or five if you count the neutral tone) that exist in modern Mandarin. Cantonese has six tones, or nine if you count the three represented by end-sound words. End-sound words are those where you almost aspirate a sound, but don't. Say "sick" aloud for example: we say SIK-kuh. The kuh sound is the air released from our throats. In Cantonese, and many other Chinese dialects, the air is not released. It is held. In this, it is similar to ancient Chinese: ancient poetry sounds better in dialects such as Hokkien and Cantonese simply because they are less adulterated, the similarity is greater, than Mandarin.
But that history is not an issue. The only issue for me is that I'm in Canton, the beat of this land is Cantonese and I'm finally starting to dance to its beat.