Snippets after latin letters

How can insert snippet, no matter what is before it? It just does not work after lating letters. For example, I made snippet that convert two spaces to _ (space for trigger and space for shortcut), but it works only if not after English letters, so it is useless: some_text -- I need this without typing shift+- some(space, space)text -- not working, just two spaces some(space, space, space)text -- some _text (first space is not used) 字(space, space) -- 字_ (working as 字 is not latin character) How can I use snippets no matter what is before them?