This is true, but it is a massive job to do this translation so it does not get done. Many scientific concepts are only known by a handful of people in the world (i.e. those formed at the cutting edge) and are only able to be expressed in English.

There is nothing inherently superior about English as a language (other than it being my native language), just that it is the common language of science and so it is the language in which the majority of new concepts are communicated.