As, for the past 10 years, I have been teaching English to speakers of other languages, it's a fun social experiment to become a language learner again. Most often, I am reminding myself to "practice what I preached."
For example, I recommended my students find patterns in language. Sometimes, people are mystified by learning a second language. Well, you learned one to the point of proficiency: reading, writing, speaking, listening. So, have some confidence, you can learn another.
All too often, I find people get stuck at the word level in their second language. Here's a common thought, "if I learn 50 words a day, at the end of a year, I'll have a vocabulary of 18,250 words." It is important to have a good memory in second language learning. However, in addition to some memorization using flash cards, I advocate the pattern identification process.
Here are some examples of word groupings (different parts of speech of a concept):
In English class I would teach:
-ist ending is for people: Communist, chemist, guitarist, flutist...
-ican ending is for nationalities: African, American, Mexican....
micro- means really small: microscope, microscopic, microphone....
chemical (adj.) chemisch*
chemical (n.) e Chemikalie*
chemist r Chemiker*
chemistry e Chemie*
Mexico s Mexiko
Mexican adj. mexikanisch
Mexican n. r Mexikaner/e Mexikanerin
microphone s Mikrofon
microscope s Mikroskop
microscopic adj. mikroskopisch
communism r Kommunismus
communist r Kommunist
Let's see how this technique can transfer to learning German (á la "practice what you preach"):
auf Deutsch (in German)
-isch= languages = Englisch, Ungarisch, Franzözisch, Italienisch, Spanisch...
-er= people = Amerikaner, Deutscher, Franzözer
-ismus= idealogies/philosophies= Kommunismus, Sozialismus, Kapitalismus...
In conclusion, by looking for the patterns (in this case meaning prefixes and suffixes), I am able to expand my vocabulary more rapidly than just rote memorization of individual words.