The mechanization of translation of texts from one language to another has been a great problem ever since linguists, computers and computer programs exist as such. People tried to develop programs to make translation easier, to make machines able to translate a text without human, manual help. However, these attempts have not succeeded fully. Nowadays, translation programs are able to produce a "raw" translation of a text, but afterwards there is great need for revision and editing, which necessarily involves the work of a professional translator. The nature of languages in itself is an obstacle to the full mechanization of translation. You can think of some basic, simple examples, even if you have never dealt with machine translation or linguistics, but you know at least two languages. For example, there is no one-to-one correspondence between words of two different languages. There are even words or expressions in a language that have no exact equivalent in the other language, in extreme cases the notion itself does not exist in the other language, so there is no word for it. Apart from vocabulary-based problems, there are also syntactic obstacles, and many other aspects that will be shown later on.