On my 5X I can make it fairly small. http://i.imgur.com/7pA0Vzj.png

On my Amazon Fire 5th gen (the $50 one) the smallest is still pretty big. http://i.imgur.com/82NC0By.png.png

On both devices, in the regular Termux application, I can make the text as small as I want.