This week’s chapter of the textbook contained a lot about changing nouns into adjectives and vice versa using suffixes, and modifying adjectives using prefixes, including making negative adjectives. English has rather too many ways of making negative adjectives, including a-, dis-, il-, im-, in-, ir-, –less, non– and un-. Of these, a– is the most restricted and the textbook didn’t even mention it. il-, im-, in– and ir– are fairly restricted (compare illegal and unlawful), and –less can only be added to a noun. The three most general are dis-, non– and un-, probably in that order of restriction: we can say ‘uncool’ and ‘non-cool’, but we can’t say ‘discool’. (There are restrictions on the root adjective as well: we can say ‘unhappy’, but probably not ‘unsad’ and certainly not ‘unmiserable’.)
We have sets of words like comfort (verb), comfort (noun) and comfortable, but discomfort and uncomfortable. uncomfort and discomfortable exist, but are vanishing rare. Sometimes two adjectives sit side by side. Some combination of dissatisfying, unsatisfying, dissatisfied, unsatisfied, dissatisfactory and unsatisfactory cropped up in one lesson. dissatisfying and unsatisfying seem to be more subjective and dissatisfactory and unsatisfactory seem to be more objective: a movie might be unsatisfactory because of the picture or sound quality, but unsatisfying because of the story or acting.
Dictionary.com lists unsatisfactory, dissatisfactory, unsatisfying and dissatisfied, but dissatisfying redirects to dissatisfy, and unsatisfied to satisfied. On the other hand, unsatisfy and unsatisfaction don’t exist; the verb and noun are dissatisfy and dissatisfaction. Google Ngrams shows unsatisfactory and dissatisfied considerably ahead of unsatisfied and unsatisfying, slightly ahead of dissatisfying and dissatisfactory. So unsatisfactory and unsatisfying are clear choices, while dissatisfied is the better choice, but unsatisfied is not ‘wrong’. But there are two differences. The first is grammatical: Google Ngrams shows that dissatisfied is standardly followed by a function word (dissatisfied with, and, that, in, as, at, because, than, by and to) (and is therefore standardly used predicatively), while unsatisfied is followed by a noun more often than not (unsatisfied with, and, demand, desire, in, by, desires, longing, longings and curiosity) (and is therefore used attributively and predicatively). The second is semantic: people and demands, desires, longings, and curiosity can be unsatisfied, but only people (and maybe larger animals) can be dissatisfied.
Shakespeare has Romeo ask ‘Wilt thou leave me so unsatisfied?’, but we can hardly draw any conclusions from on random example from more than 400 years ago.