Is there anything more fun than parsing strings? I submit to you that there is not. I'm currently reading my way through Parsing Techniques - A Practical Guide, which has a first edition free online. (I'm hoping Santa brings me a copy of the 2nd edition this year.)
This is a good book, with enough math to be rigorous but not so much that it's completely unreadable. It starts from the absolute basics ("What's a grammar?") and goes through the Chomsky hierarchy and then dives into parsing techniques in great detail, in a language-agnostic way.
Languages and grammars are fascinating. In high school I studied Spanish, French, Latin and German, largely in my spare time. When I was 16, if people asked what I wanted to do for a living, I said "translator".
The plan to become a translator failed partly because the quality of my early education was horrendous and partly because mastering a language is extremely difficult and at 16 I wasn't motived enough. And then computers showed up in my life, which gave me a never-ending supply of languages to play with, while being fun (and profitable) in so many other ways. But I still took two years of Japanese classes in college for no reason other than enjoyment, and I'm still trying (and failing) to learn Japanese in my spare time 8 years later.
Perl was my first favorite language probably for no reason other than regular expressions. I can understand how people call PCRE syntax line-noise, but to me it's beautiful line noise. I live and breathe regular expressions nowadays. My favorite CS class in college was one where we went through and laboriously built finite-state automata and pushdown automata and Turing machines. Seeing the equivalence of these simple machines with the different classes of grammars was a huge epiphany. Such a simple concept with such huge consequences.
Besides a mathematical inclination, an exceptionally good mastery of one's native tongue is the most vital asset of a competent programmer.
I strongly agree with that sentiment. People tell me at times that I'm good at written communication. I have my doubts, and anyways I find it funny because I'm so terrible at verbal communication. I think if I have any success at writing, it's because I view writing as a mechanical process.
I told a prof in college once that I felt like my papers wrote themselves once I had an idea in mind. There are rules of grammar and style, and you learn them and follow them, or break them deliberately if you have a good reason to. You write some prose, then you debug it until it "works" mentally. I don't care about typos and I split infinitives and comma-splice on purpose, but ambiguous or awkward phrases usually stand out to me like compiler bugs in my brain.
What's more important than language? Few things. Language is important enough to be nearly hard-wired into our brains. Children learn it instinctively. Human beings can still easily and effortlessly out-perform the best supercomputer at the task of parsing and interpreting speech. We think in words. The programming languages computers understand are dirt-simple by comparison, but writing code still feels like writing "thoughts for the computer" sometimes.
There are very few times you'll hear me say "What a wonderful world we live in". But one of those times is when I have the opportunity to explore an area of study like language. It's such an enjoyable experience to struggle and try to master such a thing. It's an amazing universe where we have these weird little rules and they work and we can understand them and manipulate them and produce things with them.