Here is a quick rundown on the history of subtitles:
During the silent movie era, what is called ‘intertitles’, most widely known as ‘title cards’ were used in place of speech or complex narrative in a movie. Title cards are ‘boxes’ of text inserted between footages, and they were a central aspect of the storytelling process. They could be seen as similar to voiceovers today and were easily translated, and so ideal for foreign audiences.
It wasn’t until around 1920 that technology made sound possible for movie production. As you would expect, audiences were hooked by sound. Characters became more real; storytelling became more complex. There was only one problem. The introduction of sound led to the redundancy of title cards. Filmmakers would then need to dub films in order to reach foreign audiences. Subtitles were created due to the expense involved in otherwise entirely re-filming movies with foreign dialogue or dubbing a foreign voiceover with the original video.
Subtitles would indeed bridge the gap between title cards and audible speech. Dialogue would appear at the bottom section of the screen, and could be translated in order to be read by foreign viewers without any need to interrupt the flow of the film.
Nowadays, subtitles and closed captions are widely used across the world. Subtitles from Original Versions are translated into different languages to be watched by foreign audiences. They can be enabled on VoD services, broadcast programmes, video sharing sites, and on DVDs. There is an increasing trend towards using subtitles for educational purposes; for people wanting to learn foreign languages as well as for helping children to learn to read. Subtitles have been accepted over the years as useful in education.