The standart text/html modue supports only one kind of contect that is "text/html". It does nt upport witching to other languages
You have two options:
1) You can use a langeuage enabed module, like the MMLinks module found free in this site. This module allows you to enter text or each language (Also it supports some cool effects)
2) You can use DSLocalizator to help your localization to work. You can dropt two instances on the text/htm module and then tell DSLocalizator to hide one module per each anguage....so will will only ee one module when a specific language is selected and this will simulate language support for your module.
Hope it helps