Abstract: The invention relates to calculation expression management. In general terms, a calculation expression is a union of variables, constants, operators functions, delimiter characters and other possible elements, which can be used to product a result. A sample calculation expression is as follows: “2*3+A*(2+B+C)”. The uses of calculation expressions include the creation of formulae, the formation of strings and the implementation of searches for databases. The invention facilitates the implementation of sophisticated calculation expressions. For said purpose, the invention consists in constructing and evaluating calculation expressions from graphical structures representing trees. The graphical structure scan be of various different types.

Abstract: The present invention provides assistance for a person to better comprehend the samples of a target language and, simultaneously, it facilitates that the person learns that language better. In order to do that, some special perspectives on those language samples are provided, and those perspectives show in a simple form the internal structure of said samples. All this will facilitate the person the assimilation of the structure and meaning of those language samples. The invention is based on two facts. First, linguistic research has show that language comprehension depends on the assimilation of the internal structure of the messages that are received. Second, language learning require the learner to comprehend messages of that language in order to be able to develop the competence to associate meaning and form.

Abstract: The invention is intended to facilitate language learning by improving sound identification and perception. It is well known that foreign language students in particular have great difficulty in mastering the sounds of the foreign language being learned. Among other possible causes, this is due to interferences that occur between the written form of the target language and the sounds that the students associates mentally with used in the written form. In the case of foreign language learning, the aforementioned association comes fundamentally from the native language of the learner. The invention relates to a training method for learning languages involving the use of graphic entities which enable the sounds of the target language to be manipulated without creating interferences between the writ en and spoken form.