Cognitive Psychology
1. Taking into account that there is no universal sign, cross-cultural communication is a very abstract notion. The differences in culture and subcultures are the grand barriers to communication. Depending on the topic that people are discussing, this cultural gap may become either very broad, or it can be minimized. However, generally cross-cultural communication is possible because of the concepts familiar to any person on the planet.
Because every language is unique, it is also different. One concept in English language may sound absolutely different in say Russian or Japanese. Pronunciation does not count here, but rather the words that are used. If we take one concept and say it in different languages, and then translate word-for-word, each exact translation would be different. There are two words for “you” addressing either one or several persons in many languages, but not English. However, the meaning that we convey with the speech does not change, only its cover may vary with languages. Therefore, even though every language is different, they all are the same in terms of meaning. 
The idea of one official language for all countries and nations is great at the first glance, because everyone would be able to communicate freely. However, the cultural differences one official language is unable to overcome.
2. Developing and storing concepts and knowledge in general is much more useful for humans than for any other being on the planet, mostly because we use our brain to survive, not our body. With certain knowledge in a particular field, one can serve society and make money, and also make more accurate decisions in various situations. We do need knowledge because we use it, and the more we know the better. However, there are disadvantages of knowing things as well. Some concepts may develop stereotypes, which are false. Another concepts may develop prejudice, which are also false. Finally, we could simply develop false knowledge of things, which would in turn lead us to inaccurate decisions and even problems. 
Some things we experience are important, some are less important, yet some are not important at all. We tend to automatically categorize things by their importance, but every person is distinct in his or her categorization. Depending on many factors such as experience, traits, occupation, age, and some more, two people may perceive one and the same event differently, labeling it under different levels in this hierarchy. A computer may mean one thing for a child who only plays game, another thing for a programmer, and yet completely another thing for a factory worker who assembles this computer. 
Just like there are millions of sectors on a hard drive, human brains also store information in little portions. It is easier for us to memorize a phone number in 3 groups of numbers rather than the entire number as whole. This explains the connectionism of our memory.
3. It is impossible to tell for sure whether this statement is logical or not, “If John kicks his dog, Mary will eat spaghetti. Mary won't eat spaghetti Therefore, John did not kick his dog.” However, if the connection between the former and the latter is reciprocal, then this statement is true. Otherwise, there is no proof that there are no other events that may entail Mary eating spaghetti. Plus we do not know whether kicking a dog is the only determinant of Mary to eat spaghetti. 
4. From the standpoint of cognitive psychology, I would define creativity as the ability to make up new ideas and generate new concepts. A creative person not only stores information, but also creates something new. One of the methods to measure creativity would be to set a certain time frame, and to have the person generate new ideas and concepts on a particular topic. For example, to count how many useful methods one can make up to use a simple cup, without filling it with liquid. The more useful ways to use it a person has generated, the more creative this person is. 
5. Christopher Ramey suggested rather interesting ideas, but to make a long story short, I cannot agree with his theory. In many things he is right. However, society, which consists only of human beings (at least as I know it) would naturally fail to treat robotic copies of people as full members of society. Even though such behavior, Remey argues, means dehumanizing self, the only chance for androids to be treated equally is to simply conceal their real origin and nature. It remains uncertain to me which self Ramey means, but as I understand the topic of concern, dehumanization will only occur within the androids, caused by unequal positions in society. It may be that dehumanization of self in real humans would occur, however the classic concept of self would become blurred with androids becoming members of society, whether full or not. 
Ultimately, I believe that even if the shift of the concept of self would occur, it would not be caused by the inappropriate attitudes toward androids, but by the initial inclusion of androids into society. Thus, dehumanization starts from the inverse end, from the very introduction of androids into the domain that has comprised humans only since its inception. And as for equality, androids would never reach the status of a human being, and thus would not be accepted as full members of society. The economic benefits might be obvious, but the psychology of people is in my opinion at risk of dehumanization should the intrusion of androids occur.