At least in my grad program we called them either "textural models" or "language models" (I suppose "large" was appended a couple of generations later to distinguish them from what we were doing). We were still mostly thinking of synthesis just as a component of analysis ("did Shakespeare write this passage?" kind of stuff), but I remember there was a really good text synthesizer trained on Immanuel Kant that most philosophy professors wouldn't catch until they were like 5 paragraphs in.