Sentence Spacing in Emacs

I don’t end sentences with a double space. But since type writers, some people end sentences with two spaces.

By default, Emacs considers that sentences are terminated by two spaces. I’d assume this is contrary to the expectation of most modern users. To change this, set sentence-end-double-space to nil:

(setq sentence-end-double-space nil)

This will, for example, affect the behavior of M-x fill-paragraph, which by default introduces double spacing when joining lines.