Taigu-Hyogen, literally 'Attitudinal Expressions' will be defined as a class of expressions which convey respect, derision, equality or other attitudes arising from the relation of the speaker to the listener.
In the teaching of Japanese, difficulties accompanying Taigu-Hyogen lie not only in the introduction of words and their inflected forms themselves but also in teaching how to use 'Attitudinal Expressions' each in its proper way depending upon the relation of the speaker to the hearer.
Although Keigo is generally understood as honorifics or expressions of respect, in light of current usage the term is more conveniently defined as expressions to convey the speaker's formal attitudes toward other people so that we could better explain the contexts or situations in which Keigo expressions occur.
The relationship between respectful speech and behavior to Keigo itself is self-evident. But at the same time it is also necessary to explicate the Japanese way of thinking which provides the cultural underpinning for such speech and behavior. This will lead foreign students of Japanese to a full understanding of the Japanese language.