In the Southern Netherlands (now Belgium and Luxembourg) developments were different. Under Spanish, then Austrian, and then French rule standardisation of Dutch language came to a standstill. The state, law, and increasingly education used French, yet more than half the Belgian population were speaking a Dutch dialect. In the course of the nineteenth century the Flemish movement stood up for the rights of Dutch, mostly called Flemish. But in competing with the French language the variation in dialects was a serious disadvantage. Since standardisation is a lengthy process, Dutch-speaking Belgium associated itself with the standard language that had already developed in the Netherlands over the centuries. Therefore, the situation in Belgium is essentially no different from that in the Netherlands, although there are recognisable differences in pronunciation, comparable to the pronunciation differences between standard British and standard American English. In 1980 the Netherlands and Belgium concluded the Language Union Treaty. This treaty lays down the principle that the two countries must gear their language policy to each other, among other things, for a common system of spelling.

What was the old name for the geographical region that's now Belgium and Luxembourg?