What's a word? (A quick test - how many words were in the previous sentence, maybe 3 or 4 depending on whether the 's is part of a word; so can we talk about J

What's a word? (A quick test - how many words were in the previous sentence, maybe 3 or 4 depending on whether the 's is part of a word; so can we talk about Jóhannesson's foreign policy?). It's hard enough to know what a letter is in unicode. Breaking things into words is just another massive headache.