With the development of the comics industry in the 20th century, the appearance of speech balloons has become increasingly standardized, though the formal conventions that have evolved in different cultures (USA as opposed to Japan, for example), can be quite distinct.
Med den växande serietidningsindustrin under 1900-talet standardiserades pratbubblornas utseende mer, men de formella konventioner som har utvecklats i olika kulturer (exempelvis USA jämfört med Japan) kan skilja sig märkbart.