orthography - reestablish vs. re-establish - English Language Usage . . . English fiction: reestablish is preferred; Another benchmark that can be used to gauge usage is Google Trends which examines web searches (along with other criteria) The AmE trend comparison for reestablish vs re-establish (and reestablished vs re-established) further confirms that the hyphen-less variants are the ones preferred
orthography - How can enforce and reinforce have slightly different . . . Your spellchecker is rather poor, I'm afraid However, you have to run your fingers through some seven centuries of variations in spellings of enforse, enfoarce, enforce, inforse, inforce, rainforce, reenfors, reënforce, re-enforce, reenforce, re-enforce, reinforce, and several more besides those to have any hope of making some sense of it all
hyphenation - English Language Usage Stack Exchange compounds in which a vowel would be repeated (especially to avoid confusion): co-op, semi-independent, anti-intellectual (but reestablish, reedit) compounds consisting of more than one word: (poster's note: these are phrasal adjectives) non-English-speaking, pre-Civil War