Multi-lingual text collection hide more complexities than it initially look like, because, in addition to differences in character sets and words, text analysis makes intensive use of statistics as well as the linguistic properties (such as conjugation, grammar, tenses or meanings) of a language. These language dependencies need to be addressed when dealing with non-English content
Only a few system developers offer their products for more than two or three languages. Typically, they develop the tools for one language and then adapt them to the others