Beli Tsar wrote:
Obviously when the language in question is Mandarin, though, a lot of the knowledge from say, German, isn't particularly helpful...
That is true in regard to vocabulary, phonology, and language-specific syntax, but to my surprise, there is one important way in which having learned German
IS helping me with Chinese, and it will probably help me with any further languages I decide to acquire.
I'm currently learning Mandarin Chinese in a classroom context (first semester in a community college course). Some students know more vocabulary than I do, or have better pronunciation (especially the ones with Chinese-speaking boyfriends, the benefits of which cannot be overstated), but there is one thing I'm able to do better than anyone else in our class of twelve students: I can mentally manipulate the grammar much more easily and automatically than my classmates can.
Our textbook is full of grammar practice activities that require us to perform some kind of syntactic transformation in response to cues or questions. After we have rehearsed such a task in pairs, the teacher calls on each student to recite aloud the "answer" to one of the exercise items. I use the word "recite" because that is exactly what almost every other student in the class does. They write out their responses in full (usually in pinyin) and then simply read them aloud. I think I'm the only student in the class who never pre-writes oral responses. When the teacher calls on me, I glance at the cue in the book and then construct the answer in real time, doing all the processing in my head.
Some of the other students have asked me how I'm able to do that. The answer is that learning German taught me that skill. German was the first language I studied that has case grammar. It was very difficult at first, and like most beginning students of German, I spent the first few months speaking incredibly slowly as the gears churned in my mind, desperately trying to get all the case endings right in time for the words to come out correctly by the time I reached them in my spoken utterance. Also like most students of German, there came a day when I woke up and was suddenly able to do it all practically unconsciously, without having to focus so much attention on the word endings. Lining up the articles, adjective forms, and noun endings by gender, number, and case became second nature to me, and that was when I felt I had achieved real fluency. All of the visible struggle was gone, and I became able to speak quickly and keep up with native speakers.
Quite unexpectedly, that skill has turned out to be transferable. It helped me when I went on to learn some Russian (which has even more cases than German), and now it is helping me with Chinese. I'm convinced that what makes me the best in the class at speedily processing those mental permutations that we call "grammar" is the fact that I built up that cognitive muscle when I learned German. I expect it will help me acquire the grammatical patterns of any language I study in the future. I wouldn't say that I got that same assist from French, which I learned before German. French grammar is easy for a native speaker of English. German, with its genitive and accusative and dative cases and verbs postponed to the end of a dependent clause, presents much more of a challenge (and Russian still more), but scrambling up that steep hillside turned out to be worth the struggle. It gave me a facility with grammar that is proving to be useful far beyond the confines of the language family in which I first developed that skill.
My next language after Chinese will be Japanese, and while I expect my learning of Japanese kanji to receive a boost from my knowing some of the Chinese Hanzi from which the former derive, I'll also be playing close attention to whether the general ability to learn characters is also a skill that grows easier with time and practice, especially in the case of kanji that are specific to Japanese and totally new to me. I'll get back to you in seven years on that.
