In some languages (well, at least in Slovak), it is a typographical error for a single-letter word to stand at the end of line. This webpage contains primitive javascript code that lets you convert tex source files with slovak content to such form that all one-letter words will be followed by no break space (tilde "~" character).
Beware, this software is buggy, it is therefore advised to a) maintain a backup copy of the original file, b) inspect the output for misplaced tilde "~" characters.
All of the code runs inside the browser, you needn't worry about your work being stolen. It stays on your computer during the whole process, no data is being sent to the server.