During my last term of my undergraduate degree, I had a few elective credits to burn, so I decided to take Mandarin. I had several motivations for this. Firstly, I wanted to prove to myself that I could learn to write Chinese. I never picked up writing Chinese as a child simply because I never used it. Secondly, I wanted to improve my Chinese language skills in general. UVic doesn't offer courses in Cantonese (my native tongue), but they did offer Mandarin which was the next best thing. Lastly, I wanted to learn Mandarin for job reasons. Knowing Mandarin will be handy as China is rapidly emerging as a world power, and there are a number of jobs that smile upon individuals who know English and Mandarin. When I had applied to a few government agencies for co-op work, I noticed that the government has several languages that they really liked in their employees, and Mandarin was one of them.
Some background before we start. The first language I learned was Cantonese, simply because that's the language my parents speak. Living in Canada meant that I didn't really use Cantonese that much, so I lost most of my Chinese writing skills. As I attended school, English became my most proficient language. However, I can speak Cantonese fairly well, and my ability to listen and understand Cantonese is even better. For example, I can sit through a Chinese movie and understand a good chunk of it, and probably translate it to English. Language number three was learning French in school. I'm not sure how much French I have retained.
Anyways, learning Mandarin was very interesting for me as a person who spoke Cantonese which is a Chinese dialect. For those who don't understand what a dialect is, a good example would be like English and Ebonics. There are many similarities, and many many differences. However, if you tried really hard, you could probably figure out approximately what someone in a different dialect was saying.
Orally, Mandarin was pretty easy for me to learn. Speaking Chinese depends heavily on the tone in which you speak a word. A word with the same sound but with different tone will have very different meaning. For example, the sound "say" could mean "four" or "die" depending on what tone you use. Easy no? In either case, Mandarin has four different tones, while Cantonese has nine different tones. So going from Cantonese to Mandarin is probably easier than the inverse.
As far as learning the vocabulary and grammar, it wasn't too bad. A lot of the times, if I didn't know a certain word in Mandarin, I could make an educated guess using my knowledge of Cantonese. Sometimes I would be totally off because a word in Cantonese would not exist in Mandarin, or the word was pronounced completely differently. Learning the grammar was very interesting to me. The grammar for Mandarin and Cantonese is the same (i think). I only knew Chinese grammar rules implictly, but I would never be able to formally state them. Learning the grammar formally made my Chinese better, and a bunch of light bulbs went off... as I could go... ohhhh... that's why we say things that way.
Learning the Mandarin grammar has made me realize just how complicated English is. In Mandarin, we don't have to worry about past-tense, future-tense, etc, etc. Tenses in English is rather confusing, especially since it's not consistent. I remember one of my computer science teachers was explaining how 3 year olds will get English grammar wrong because it is inconsistent. For example, a child will learn the different tenses for the word
ring as: ring, rang, rung. For the word
bring, the child will implicitly guess that the tenses would be: bring, brang, brung. However, this is incorrect as it should be: bring, brought, brought. In Chinese, we don't have to worry about tenses as we can figure out what tense you're in based on the context of the sentence. The grammatical rules seem to be more consistent than English as well (although not perfect).
I also noticed that Chinese sentences were much more concise than English sentences as we don't have filler words and other fluff. When we had to translate Chinese sentences to English sentences, I always found that the English sentence required a lot more words.
Based on these two observations, I now understand why foreign Chinese students have such a hard time picking up English. If you were to take a Chinese sentence, and translate it word for word to English, it makes
Engrish. For example, the phrase "wo da si ni" which means "I'll beat you to death" will translate to "I hit death you" if you were to translate it word for word. Again, notice how short the Chinese sentence is compared to its English counterpart.
The hardest part about Mandarin was the writing. Chinese uses symbols/characters to represent words. We do not have an alphabet, so one needs to memorize the symbols. By looking at a Chinese word, you cannot phonetically sound out and guess what the word means. Chinese characters usually contain a root symbol called the radical, which will allow you to guess very generally what the character is related to. For example, a complex symbol may contain the character for "heart", so you can guess that the overall symbol has something to do with heart or emotions. I found memorizing Chinese characters was difficult especially if I didn't use them often. I know even my parents have difficulty recalling Chinese characters, even for very commonly used Chinese words.
An annoying issue with Chinese writing is that there is a traditional version and a simplified version. Basically, the communists in China wanted to boost literacy rates, so they simplified Chinese characters by reducing the number of strokes in characters. The wikipedia has a good article about
simplified Chinese. Most Chinese people that lived outside of communist China learned traditional Chinese. So people from Hong Kong for example used Traditional Chinese. Since I dislike communist China, I have taken the anticommunist stance, and have learned Traditional Chinese

.
Simplified Chinese sometimes looks completely different from traditional Chinese characters, so it's kind of annoying (and ugly). Furthermore, someone who knows traditional Chinese could probably guess/figure out what Simplified Chinese characters mean; however, the inverse cannot be done.
In addition, Simplified Chinese has also introduced ambiguities. In Traditional Chinese, every word has a distinct character. In Simplified Chinese, this is not the case, a single character can have many meanings. A good example of this would be an example from English, as it has this problem. Take the word "free" for example. On its own, free is ambigious. Does it mean free as in free beer? Or does it mean free, as in liberty? Simplified Chinese has the same problem.
The other interesting thing that I learned was that Cantonese is more of a spoken language. A lot of the words used orally cannot be written, as the Chinese characters were never assigned to them. In English, something like that would be pretty straightfoward, as you would phonetically spell out your word, and it becomes a word. For example, I can write "shizzle" and voila, I have a word.
In either case, learning Mandarin was very interesting as I wanted to improve my Chinese. It was an ego booster as there were a number of white people in my class, and they were no match for my asian powers j/k

. I think I finished the final exam in 45 minutes, and the exam was supposed to take two to three hours (and I bumped into Marley after that exam). Anyways, I would have loved taking more Mandarin courses if I had university credits left. Maybe in the future, some employer will pay me to learn more Chinese, that'd be sweet.