I wonder if your article will revive the popularity of the phrase. https://books.google.com/ngrams/graph?content=special+register+groups&year_start=1800&year_en

I wonder if your article will revive the popularity of the phrase. https://books.google.com/ngrams/graph?content=special+register+groups&year_start=1800&year_end=2022&corpus=en&smoothing=3 https://books.google.com/ngrams/graph?content=special+regist...