So how do you tell TeX where the ends of sentences are? I rather like the simple interface that is 'press space bar twice'. Do I have to put something on abbreviations instead?
Just in case that sounds too simple, there is an exception for initials: `P. G. Wodehouse` is treated the same as `P.\@ G.\@ Wodehouse`. If you want to cancel this, prefix the period by `\@`.
This kind of thing makes Latex a hard sell to a general audience.
See http://latex-alive.tumblr.com/post/827168808/correct-punctua...
For abbreviations, you should explicitly insert a space control sequence (\<space>) or a non-breaking space (~) after the period.