vocabulary

why the repeat posts? Your first query has answers.
http://able2know.org/topic/307626-1

http://www.sk.com.br/sk-krash-english.html

I think it's difficult to master any languages in adult. What do yo think?

It's definitely difficult. The #1 factor is motivation. After that, opportunity. What's your native language, and which one are you going to learn?

Yeah I think so. But each people is different, all right?
I want to ask you a question. How to master vocabularies easily?

A lot depends on the relationship between your native language and the target language. For example, English and Spanish share a lot of very similar and related vocabulary. When I started learning Spanish, I started with the words most similar to English, then gradually expanded my focus on less familiar words.

Korean and English, however, have nothing in common except for "Konglish," which is not really Korean, not really English.

Some general tips:
Flash cards have been proven to be very effective.
Study phrases instead of single words whenever possible.
Study the vocabulary in a memorable context.
Short and frequent study periods are more effective than longer classes that are spaced out.
Keep a diary (in your native language, at first) of your study times and topics. Write down what you studied (topic) and how long you spent studying it. This will help the information get stored in long-term memory.
Whenever possible, use your ears to learn pronunciation, not your eyes.
Study material should be 80~90% easy. That is, mostly repetition of what you already know.

Ok. I know what you mean. Thanks a lot.
What different techniques do you have for learning vocabulary?

These days, when I find a new word that's useful, I write it down on my hand, on the skin between my thumb and index finger. Then, during the day when I use my hand, I read the word again and remember what it means. At the end of the day, I usually have 3~4 new words or phrases. In the beginning, though, I used flash cards a lot.

Oh, I think it's a good method, yeah.
Maybe it can be done by conversations. Simply talking with other people can help me to learn discover new words. As with reading, once I hear a new word, remember to jot it down so that I can study it later and then slowly add the new word to my vocabulary. Right?

Yep. That sounds good to me. Best of luck!

Yeah..
Is the classroom the best place to learn?Can a good teacher influence how well you enjoy learning a language?
What do you mean about that?

Most classrooms are not ideal places to learn a language, but it depends on the teacher. If s/he is good at applying language acquisition theories and approaches to the class activities, then they can be very effective, though. It's important to have enjoyable and meaningful communicative activities, rather than too much memorization and grammar focus. Too many teachers depend on obsolete approaches, though. Enjoyable and meaningful communicative activities help you learn implicitly, which sticks in long-term memory better than explicit teaching. That said, I learned a lot more Spanish by going to Mexico and Central America than I ever did in a classroom. I've also learned a lot more Korean outside of classrooms than in them. If you're in a position to immerse yourself in the target language environment, you'll do fine. You seem to have the motivation already.

Creating a positive learning environment in classroom will allow students to feel comfortable, safe and engaged something that all students deserve. In a classroom where values and roles remain constant and focus is placed on the positive aspects of learning, students will be more open to actively participating in class.
But, what is a negative classroom environment?

A negative classroom environment is, in my opinion, any environment that prevents a student from performing at his/her best. Fear of ridicule or punishment, for example, or where the target language doesn't meet the Input Hypothesis. The learners should feel encouraged to explore, experiment and discover for themselves, rather than just copy the teacher's output.

Yes, right! But it's positive classroom environment. Student can be more active in clasroom.
In addition, a negative classroom environment, maybe by punnishment, student can be fright and fright. So it makes student be fright to try using foreign language.