The first to chime in was Susan Lin, an assistant linguistics professor at the University of California Berkley. In a post to the Facebook group Friends of Berkley Linguists, Lin took a crack at getting to the bottom of the debate. "'Bigly' or 'big league'? The latter, I'm quite sure," Lin wrote.
The evidence, she says, are in a spectrogram of Trump saying the mystery word(s). A spectrogram creates a visual representation of spoken language and pronunciation. The bigly evidence? That the spectrogram shows Trump adding a second "G" sound at the end of the phrase.
That means it's "big league," folks.