In memetics, there are many wildly-different memetic codes. Each human language represents a memetic code. The same goes for each computer programming language. There are millions of such langages.
An incompatible genetic code acts as a barrier to gene transfer. It represents a deeper divide than a species division - since this can be routinely bridged by horizontal gene transfer mediated by viruses. Similarly, incompatible memetic codes hinder the spread of ideas. However, technological progress in modern times has led to sophisticated machine translation tools. We can now often translate from one language into another - and from one computer programming language into another.
Incompatible memetic codes have been a big barrier in the past to the spread of ideas. Now it looks as though these barriers are coming down - or at least becoming much less severe. For memes that means a bigger and more diverse meme pool and more prospective recombination partners.
In a well-known biblical fairy tale, god saw that man was getting over-ambitious and divided him into tribes and gave him a fragmented linguistic heritage. It looks as though we are beginning to work around that issue. Soon it will be tower-building time once again.