T-glottalization's a process that occurs for many English speakers, that causes the phoneme /t/ to be pronounced as the glottal stop [ʔ] in certain positions. The earliest mentions of the process are in Scotland during the 19th century, when Henry Sweet commented on the phenomenon. David Crystal claims that the sound can be heard in RP speakers from the early 20th century such as Daniel Jones, Bertrand Russell and Ellen Terry. The Cambridge English Pronouncing Dictionary claims that t-glot… (More on T-glottalization)